feat(commands): tier-1 — translate, math, theme toggle, project opener, sound panel

Five more portable Lua command packs. Bumps the total from 16 to 21
packs. cargo test -p jarvis-core --lib commands::tests still 3/3.

translate/ — translate.lua. Picks the target language from triggers
like "переведи на английский" / "translate to russian"; falls back to
English when only "переведи X" is heard. Sends to Groq with a strict
"translation only" system prompt at temp 0.3. Drops the result into
the clipboard, fires a notify, and speaks via PowerShell SAPI in the
matching ISO voice (ru-RU / uk-UA / en-US / de-DE etc.) so a German
translation actually sounds German.

math/ — math.lua. Strips the trigger ("посчитай" / "calculate" /
"сколько будет" / "what is" / ...), sends the remainder to Groq with
temp=0.0 and max_tokens=64, asking ONLY for the numeric result. If
the model replies "нет" (the system-prompt sentinel for non-math),
plays not_found instead of speaking nonsense. Otherwise speaks
"Получилось X" via SAPI.

theme/ — set.lua dispatched by command_id (theme_dark / theme_light).
Flips AppsUseLightTheme + SystemUsesLightTheme under
HKCU\...\Themes\Personalize via Set-ItemProperty. No reboot needed,
Windows shell re-themes immediately.

projects/ — open.lua + list.lua. Reads/creates
%USERPROFILE%\Documents\jarvis-projects.json (a flat
[{"name": ..., "path": ...}] list). open.lua strips the trigger,
exact-matches then substring-matches the project name, opens the path
in VS Code if `code.cmd` is on PATH, otherwise in Explorer. First
call creates a sample config with jarvis-rust / jarvis-python /
dietpi entries pointing under USERPROFILE so it works on any machine.
list.lua just notifies the configured project names.

sound_panel/ — open.lua. Two-liner: rundll32 mmsys.cpl,,1 (Recording
tab). Useful both as a standalone "открой настройки звука" and as
the place to fix the mic-disabled state that prevents jarvis-app
from starting.

Portability: USERPROFILE / SystemDrive / PATH lookup throughout.

resources/commands/math/command.toml

@@ -0,0 +1,27 @@
+[[commands]]
+id = "math_eval"
+type = "lua"
+script = "math.lua"
+sandbox = "full"
+timeout = 15000
+
+[commands.phrases]
+ru = [
+    "посчитай",
+    "сколько будет",
+    "вычисли",
+    "реши",
+    "сколько это",
+]
+en = [
+    "calculate",
+    "how much is",
+    "compute",
+    "solve",
+    "what is",
+]
+ua = [
+    "порахуй",
+    "скільки буде",
+    "обчисли",
+]

resources/commands/math/math.lua

@@ -0,0 +1,87 @@
+local lang = jarvis.context.language
+local phrase = (jarvis.context.phrase or ""):lower()
+
+local triggers = {
+    "сколько будет", "сколько это", "посчитай", "вычисли", "реши",
+    "how much is", "calculate", "compute", "solve", "what is",
+    "скільки буде", "порахуй", "обчисли",
+}
+
+local query = phrase
+for _, t in ipairs(triggers) do
+    local s, e = string.find(query, t, 1, true)
+    if s == 1 then
+        query = query:sub(e + 1)
+        break
+    end
+end
+query = query:gsub("^%s+", ""):gsub("%s+$", "")
+
+if query == "" then
+    jarvis.system.notify("Math", lang == "ru" and "Что посчитать?" or "What to compute?")
+    jarvis.audio.play_error()
+    return { chain = false }
+end
+
+local token = jarvis.system.env("GROQ_TOKEN")
+if not token or token == "" then
+    jarvis.system.notify("Math", "GROQ_TOKEN не задан")
+    jarvis.audio.play_error()
+    return { chain = false }
+end
+
+local base  = jarvis.system.env("GROQ_BASE_URL"); if not base or base == "" then base = "https://api.groq.com/openai/v1" end
+local model = jarvis.system.env("GROQ_MODEL");    if not model or model == "" then model = "llama-3.3-70b-versatile" end
+
+local sys = "Ты калькулятор. Решай арифметику, простые уравнения, конверсии единиц, проценты. "
+    .. "Отвечай ТОЛЬКО результатом числом или короткой строкой (для уравнений — значения корней). "
+    .. "Если запрос — не математика, ответь одним словом «нет»."
+
+local payload = {
+    model = model,
+    messages = {
+        { role = "system", content = sys },
+        { role = "user",   content = query },
+    },
+    max_tokens = 64,
+    temperature = 0.0,
+}
+
+jarvis.log("info", "math query: " .. query)
+local res = jarvis.http.post_json(base .. "/chat/completions", payload, { Authorization = "Bearer " .. token })
+
+if not res.ok then
+    jarvis.log("error", "math api failed: " .. tostring(res.status))
+    jarvis.system.notify("Math", "Ошибка API")
+    jarvis.audio.play_error()
+    return { chain = false }
+end
+
+local body = res.body or ""
+local content = body:match('"content"%s*:%s*"(.-[^\\])"')
+if not content then
+    jarvis.system.notify("Math", "Не смог распарсить ответ")
+    jarvis.audio.play_error()
+    return { chain = false }
+end
+content = content:gsub('\\n', '\n'):gsub('\\"', '"'):gsub('\\\\', '\\'):gsub('\\t', '\t')
+content = content:gsub("^%s+", ""):gsub("%s+$", "")
+
+if content:lower() == "нет" or content == "" then
+    jarvis.system.notify("Math", lang == "ru" and "Это не математика" or "Not math")
+    jarvis.audio.play_not_found()
+    return { chain = false }
+end
+
+jarvis.system.notify(query, content)
+jarvis.log("info", "math result: " .. content)
+
+local sapi_text = ((lang == "ru" and "Получилось " or "Result: ") .. content):gsub("'", "''"):gsub("\r?\n", " ")
+local ps = string.format(
+    [[Add-Type -AssemblyName System.Speech; $s = New-Object System.Speech.Synthesis.SpeechSynthesizer; foreach ($v in $s.GetInstalledVoices()) { if ($v.VoiceInfo.Culture.TwoLetterISOLanguageName -eq 'ru') { try { $s.SelectVoice($v.VoiceInfo.Name); break } catch {} } } $s.Speak('%s')]],
+    sapi_text
+)
+jarvis.system.exec(string.format('powershell -NoProfile -ExecutionPolicy Bypass -Command "%s"', ps:gsub('"', '\\"')))
+
+jarvis.audio.play_ok()
+return { chain = false }