feat(gui): footer backend chips + Settings 'AI Backends' tab + i18n

Surfaces the LLM/TTS hot-swap UX in the GUI so the user doesn't need env vars
or voice commands. Tauri commands for this landed in b243e67; this commit
wires them to Svelte.

Footer (frontend/src/components/Footer.svelte)
  - Poll get_active_backends() every 5 s, show TTS / LLM / Profile chips.
  - Chips have border accents by kind (cyan = TTS, lime = LLM, orange = Profile).
  - Friendly title tooltips with full backend + model names.
  - Silent if jarvis-gui can't reach the command (e.g. cold start) — no UI flicker.

Settings — new "AI Backends" tab (frontend/src/routes/settings/index.svelte)
  - Status banner showing active LLM (with model name) + TTS + Profile.
  - LLM selector: Auto / Groq / Ollama → calls set_llm_backend on change
    (hot-swap, persisted to DB).
  - TTS selector: Auto / SAPI / Piper / Silero → calls set_tts_backend
    (persisted, effective on next jarvis-app restart).
  - "Reset context" button → llm_reset_context Tauri command.
  - Error toast for swap failures (e.g. Groq selected but no GROQ_TOKEN).
  - Tips alert: how to install Ollama / Piper / voice commands.
  - Loads prefs via db_read('llm_backend' / 'tts_backend') on mount.

i18n strings (ru/en/ua, .ftl files)
  - 14 new keys: settings-ai-backends, settings-ai-active, settings-ai-auto,
    settings-ai-applying, settings-ai-error, settings-ai-tips,
    settings-llm-backend{,-desc}, settings-tts-backend{,-desc},
    settings-llm-context{,-desc}, settings-llm-reset, settings-profile.

Build glue (crates/jarvis-gui/Cargo.toml)
  - jarvis-core dep now includes the `llm` feature so backends.rs can resolve
    `jarvis_core::llm::*` (was failing to compile after the global LLM module).

.gitignore
  - tools/piper/*.dll, piper.exe, voices/, espeak-ng-data/ — locally
    installed binaries from tools/piper/install.ps1, not committed.

Build: cargo build --release -p jarvis-gui green (4m, includes npm/Vite).
Test path: rebuild + launch jarvis-gui, /settings → "AI Backends" tab.

.gitignore

@@ -56,3 +56,15 @@ tree.txt
 
 # Tauri-generated platform schemas (regenerated on every build)
 crates/jarvis-gui/gen/schemas/*-schema.json
+
+# Piper TTS binaries (installed via tools/piper/install.ps1, not committed)
+tools/piper/piper.exe
+tools/piper/*.dll
+tools/piper/espeak-ng-data/
+tools/piper/voices/
+tools/piper/libtashkeel_model.ort
+tools/piper/pkgconfig/
+
+# Silero model cache (downloaded by torch.hub on first synth)
+tools/silero/.silero_cache/
+tools/silero/*.pt

crates/jarvis-core/src/i18n/locales/en.ftl

@@ -142,3 +142,19 @@ settings-gliner-models-hint = No GLiNER models found.
 search-error-not-running = Assistant is not running
 search-error-failed = Failed to execute command
 settings-no-voices = No voices found
+
+# AI Backends tab
+settings-ai-backends = AI Backends
+settings-ai-active = Active backend
+settings-ai-auto = Auto
+settings-ai-applying = Applying...
+settings-ai-error = Switch failed
+settings-ai-tips = Tips
+settings-llm-backend = LLM backend
+settings-llm-backend-desc = Where to run LLM requests. Hot-swap, no restart needed.
+settings-tts-backend = TTS backend
+settings-tts-backend-desc = Takes effect on next jarvis-app launch.
+settings-llm-context = Conversation context
+settings-llm-context-desc = LLM remembers previous turns. Reset if answers get weird.
+settings-llm-reset = Reset context
+settings-profile = Profile

crates/jarvis-core/src/i18n/locales/ru.ftl

@@ -142,3 +142,19 @@ settings-gliner-models-hint = Модели GLiNER не найдены.
 search-error-not-running = Ассистент не запущен
 search-error-failed = Не удалось выполнить команду
 settings-no-voices = Голоса не найдены
+
+# AI Backends tab
+settings-ai-backends = ИИ-движки
+settings-ai-active = Активный движок
+settings-ai-auto = Авто
+settings-ai-applying = Применяю...
+settings-ai-error = Ошибка переключения
+settings-ai-tips = Подсказки
+settings-llm-backend = LLM движок
+settings-llm-backend-desc = Где исполнять LLM-запросы. Hot-swap, без рестарта.
+settings-tts-backend = TTS движок
+settings-tts-backend-desc = Применится при следующем запуске jarvis-app.
+settings-llm-context = Контекст разговора
+settings-llm-context-desc = LLM помнит предыдущие реплики. Сбросить, если ответы становятся странными.
+settings-llm-reset = Сбросить контекст
+settings-profile = Профиль

crates/jarvis-gui/Cargo.toml

@@ -7,7 +7,7 @@ repository.workspace = true
 edition.workspace = true
 
 [dependencies]
-jarvis-core = { path = "../jarvis-core", default-features = false }
+jarvis-core = { path = "../jarvis-core", default-features = false, features = ["llm"] }
 tauri = { version = "2", features = [] } # v1: "shell-open", "dialog-message", "path-all"
 tauri-plugin-shell = "2"
 tauri-plugin-dialog = "2"

frontend/src/components/Footer.svelte

@@ -1,4 +1,7 @@
 <script lang="ts">
+    import { onMount, onDestroy } from "svelte"
+    import { invoke } from "@tauri-apps/api/core"
+
     import { appInfo, translations, translate } from "@/stores"
 
     $: t = (key: string) => translate($translations, key)
@@ -14,9 +17,72 @@
         upstreamLink = info.upstreamLink
         issuesLink = info.issuesLink
     })
+
+    // Active backends — refreshed every 5 seconds. Silently fails if the
+    // Tauri command isn't registered (e.g. running against an old jarvis-app).
+    interface ActiveBackends {
+        tts: string
+        llm: string
+        llm_model: string | null
+        profile: string
+    }
+
+    let backends: ActiveBackends | null = null
+    let pollId: ReturnType<typeof setInterval> | null = null
+
+    async function refreshBackends() {
+        try {
+            backends = await invoke<ActiveBackends>("get_active_backends")
+        } catch (err) {
+            // ignore
+        }
+    }
+
+    onMount(() => {
+        refreshBackends()
+        pollId = setInterval(refreshBackends, 5000)
+    })
+
+    onDestroy(() => {
+        if (pollId !== null) clearInterval(pollId)
+    })
+
+    function chipTitle(key: "tts" | "llm"): string {
+        if (!backends) return ""
+        if (key === "tts") return `TTS backend: ${backends.tts}`
+        const model = backends.llm_model ? ` (${backends.llm_model})` : ""
+        return `LLM backend: ${backends.llm}${model}`
+    }
+
+    function chipLabel(value: string): string {
+        const map: Record<string, string> = {
+            sapi: "SAPI",
+            piper: "Piper",
+            silero: "Silero",
+            groq: "Groq",
+            ollama: "Ollama",
+            none: "—",
+        }
+        return map[value] ?? value
+    }
 </script>
 
 <footer id="footer">
+    {#if backends}
+        <p class="backends" title="Активные движки. Меняются в /settings и голосом.">
+            <span class="chip chip-tts" title={chipTitle("tts")}>
+                <small>TTS</small> {chipLabel(backends.tts)}
+            </span>
+            <span class="chip chip-llm" title={chipTitle("llm")}>
+                <small>LLM</small> {chipLabel(backends.llm)}
+            </span>
+            {#if backends.profile && backends.profile !== "default"}
+                <span class="chip chip-profile" title="Active profile">
+                    <small>Profile</small> {backends.profile}
+                </span>
+            {/if}
+        </p>
+    {/if}
     <p>
         © {currentYear} J.A.R.V.I.S.
         <span class="edition" title="Rust + Tauri build">Rust</span>
@@ -62,6 +128,35 @@
             vertical-align: middle;
         }
 
+        .backends {
+            margin-bottom: 8px;
+
+            .chip {
+                display: inline-block;
+                margin: 0 3px;
+                padding: 2px 8px;
+                border-radius: 10px;
+                font-size: 11px;
+                font-weight: 500;
+                letter-spacing: 0.2px;
+                color: #cfd2d5;
+                background: rgba(255, 255, 255, 0.06);
+                border: 1px solid rgba(255, 255, 255, 0.08);
+
+                small {
+                    color: #6c6e71;
+                    margin-right: 3px;
+                    font-size: 9px;
+                    text-transform: uppercase;
+                    letter-spacing: 0.5px;
+                }
+
+                &.chip-tts { border-color: rgba(82, 254, 254, 0.25); }
+                &.chip-llm { border-color: rgba(138, 200, 50, 0.25); }
+                &.chip-profile { border-color: rgba(255, 168, 60, 0.25); }
+            }
+        }
+
         p {
             margin: 0;
             padding: 0;

frontend/src/routes/settings/index.svelte

@@ -30,7 +30,8 @@
         Code,
         Gear,
         QuestionMarkCircled,
-        CrossCircled
+        CrossCircled,
+        ChatBubble,
     } from "radix-icons-svelte"
 
     $: t = (key: string) => translate($translations, key)
@@ -85,6 +86,66 @@
     let apiKeyPicovoice = ""
     let apiKeyOpenai = ""
 
+    // ── AI backends (new tab) ─────────────────────────────────────────────
+    interface ActiveBackends {
+        tts: string
+        llm: string
+        llm_model: string | null
+        profile: string
+    }
+
+    let activeBackends: ActiveBackends | null = null
+    let selectedLlmBackend = "" // "" = auto, "groq", "ollama"
+    let selectedTtsBackend = "" // "" = auto, "sapi", "piper", "silero"
+    let backendSwapBusy = false
+    let backendSwapError = ""
+
+    async function refreshActiveBackends() {
+        try {
+            activeBackends = await invoke<ActiveBackends>("get_active_backends")
+        } catch (err) {
+            console.error("Failed to read active backends:", err)
+        }
+    }
+
+    async function applyLlmBackend(target: string) {
+        backendSwapError = ""
+        if (target === "") {
+            try {
+                await invoke("db_write", { key: "llm_backend", val: "" })
+            } catch (err) {
+                backendSwapError = String(err)
+            }
+            await refreshActiveBackends()
+            return
+        }
+        backendSwapBusy = true
+        try {
+            await invoke<string>("set_llm_backend", { name: target })
+            await refreshActiveBackends()
+        } catch (err) {
+            backendSwapError = String(err)
+        } finally {
+            backendSwapBusy = false
+        }
+    }
+
+    async function applyTtsBackend(target: string) {
+        try {
+            await invoke<string>("set_tts_backend", { name: target })
+        } catch (err) {
+            backendSwapError = String(err)
+        }
+    }
+
+    async function resetLlmContext() {
+        try {
+            await invoke("llm_reset_context")
+        } catch (err) {
+            console.error(err)
+        }
+    }
+
     // subscribe to stores
     assistantVoice.subscribe(value => {
         voiceVal = value
@@ -215,6 +276,19 @@
             gainNormalizerEnabled = gainNormalizer === "true"
             apiKeyPicovoice = pico
             apiKeyOpenai = openai
+
+            // load AI backend prefs
+            try {
+                const [llm_pref, tts_pref] = await Promise.all([
+                    invoke<string>("db_read", { key: "llm_backend" }),
+                    invoke<string>("db_read", { key: "tts_backend" }),
+                ])
+                selectedLlmBackend = llm_pref ?? ""
+                selectedTtsBackend = tts_pref ?? ""
+            } catch (err) {
+                console.error("Failed to load backend prefs:", err)
+            }
+            await refreshActiveBackends()
         } catch (err) {
             console.error("failed to load settings:", err)
         }
@@ -307,6 +381,102 @@
         />
     </Tabs.Tab>
 
+    <Tabs.Tab label={t('settings-ai-backends') || 'AI Backends'} icon={ChatBubble}>
+        <Space h="sm" />
+
+        {#if activeBackends}
+            <Alert title={t('settings-ai-active') || 'Активный движок'} color="cyan" variant="outline">
+                <Text size="sm" color="gray">
+                    LLM: <strong>{activeBackends.llm}</strong>
+                    {#if activeBackends.llm_model}({activeBackends.llm_model}){/if}
+                    &nbsp;·&nbsp; TTS: <strong>{activeBackends.tts}</strong>
+                    &nbsp;·&nbsp; {t('settings-profile') || 'Profile'}: <strong>{activeBackends.profile}</strong>
+                </Text>
+            </Alert>
+            <Space h="md" />
+        {/if}
+
+        <NativeSelect
+            data={[
+                { label: t('settings-ai-auto') || 'Авто (по env / GROQ_TOKEN)', value: "" },
+                { label: 'Groq (cloud, fast, free tier)',        value: "groq" },
+                { label: 'Ollama (local, offline, private)',     value: "ollama" },
+            ]}
+            label={t('settings-llm-backend') || 'LLM движок'}
+            description={t('settings-llm-backend-desc') || 'Где исполнять LLM-запросы. Hot-swap, без рестарта.'}
+            variant="filled"
+            bind:value={selectedLlmBackend}
+            on:change={() => applyLlmBackend(selectedLlmBackend)}
+        />
+
+        <Space h="md" />
+
+        <NativeSelect
+            data={[
+                { label: t('settings-ai-auto') || 'Авто (по env / Piper detect)', value: "" },
+                { label: 'SAPI (Windows, robotic)',  value: "sapi" },
+                { label: 'Piper (neural, recommended)', value: "piper" },
+                { label: 'Silero (PyTorch helper)',  value: "silero" },
+            ]}
+            label={t('settings-tts-backend') || 'TTS движок'}
+            description={t('settings-tts-backend-desc') || 'Применится при следующем запуске jarvis-app.'}
+            variant="filled"
+            bind:value={selectedTtsBackend}
+            on:change={() => applyTtsBackend(selectedTtsBackend)}
+        />
+
+        <Space h="md" />
+
+        {#if backendSwapBusy}
+            <Text size="xs" color="gray">
+                {t('settings-ai-applying') || 'Применяю...'}
+            </Text>
+        {/if}
+
+        {#if backendSwapError}
+            <Notification
+                title={t('settings-ai-error') || 'Ошибка переключения'}
+                icon={CrossCircled}
+                color="red"
+                withCloseButton={true}
+                on:close={() => { backendSwapError = "" }}
+            >
+                {backendSwapError}
+            </Notification>
+        {/if}
+
+        <Space h="md" />
+
+        <InputWrapper label={t('settings-llm-context') || 'Контекст разговора'}>
+            <Text size="sm" color="gray">
+                {t('settings-llm-context-desc') || 'LLM помнит предыдущие реплики. Сбросить, если ответы становятся странными.'}
+            </Text>
+            <Space h="xs" />
+            <Button
+                color="gray"
+                radius="md"
+                size="xs"
+                uppercase
+                on:click={resetLlmContext}
+            >
+                {t('settings-llm-reset') || 'Сбросить контекст'}
+            </Button>
+        </InputWrapper>
+
+        <Space h="xl" />
+
+        <Alert title={t('settings-ai-tips') || 'Подсказки'} color="gray" variant="outline">
+            <Text size="sm" color="gray">
+                • <strong>Ollama</strong>: установи с <a href="https://ollama.com" target="_blank">ollama.com</a>,
+                выполни <code>ollama pull qwen2.5:3b</code>.<br />
+                • <strong>Piper</strong>: запусти <code>pwsh tools/piper/install.ps1</code> чтобы скачать голос.<br />
+                • <strong>Голосом</strong>: «переключись на локальный» / «переключись на облако»,
+                «какой у тебя мозг» — спрашивает статус.<br />
+                • <strong>Сброс/повтор</strong>: «сбрось контекст» / «повтори последнее».
+            </Text>
+        </Alert>
+    </Tabs.Tab>
+
     <Tabs.Tab label={t('settings-neural-networks')} icon={Cube}>
         <Space h="sm" />
         <NativeSelect