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/projects/open.lua

@@ -0,0 +1,97 @@
+local lang = jarvis.context.language
+local userprofile = jarvis.system.env("USERPROFILE") or "C:\\Users\\Public"
+local config_path = userprofile .. "\\Documents\\jarvis-projects.json"
+
+if not jarvis.fs.exists(config_path) then
+    local sample = string.format([[[
+  {"name": "jarvis-rust",  "path": "%s\\Jarvis\\rust"},
+  {"name": "jarvis-python", "path": "%s\\Jarvis\\python"},
+  {"name": "dietpi",        "path": "%s\\Desktop\\Dietpi"}
+]
+]], userprofile, userprofile, userprofile)
+    jarvis.fs.write(config_path, sample)
+    jarvis.system.notify(
+        lang == "ru" and "Проекты" or "Projects",
+        lang == "ru" and "Создан шаблон в Documents/jarvis-projects.json — отредактируй и повтори"
+                      or "Template created at Documents/jarvis-projects.json — edit and retry"
+    )
+    jarvis.system.open(config_path)
+    jarvis.audio.play_not_found()
+    return { chain = false }
+end
+
+local content = jarvis.fs.read(config_path)
+
+local entries = {}
+for name, path in content:gmatch('"name"%s*:%s*"([^"]+)"%s*,%s*"path"%s*:%s*"([^"]+)"') do
+    table.insert(entries, { name = name:lower(), original_name = name, path = path:gsub('\\\\', '\\') })
+end
+
+if #entries == 0 then
+    jarvis.system.notify("Projects", lang == "ru" and "Проектов в конфиге не нашёл" or "No projects in config")
+    jarvis.audio.play_not_found()
+    return { chain = false }
+end
+
+local phrase = (jarvis.context.phrase or ""):lower()
+local triggers = {
+    "открой папку проекта", "запусти проект", "открой проект", "проект",
+    "open project", "launch project", "project",
+    "відкрий проект", "запусти проект",
+}
+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+$", "")
+
+if query == "" then
+    jarvis.system.notify("Projects", lang == "ru" and "Какой проект?" or "Which project?")
+    jarvis.audio.play_error()
+    return { chain = false }
+end
+
+local match = nil
+for _, e in ipairs(entries) do
+    if e.name == query then match = e; break end
+end
+if not match then
+    for _, e in ipairs(entries) do
+        if string.find(e.name, query, 1, true) or string.find(query, e.name, 1, true) then
+            match = e; break
+        end
+    end
+end
+
+if not match then
+    jarvis.system.notify("Projects",
+        (lang == "ru" and "Не нашёл: " or "Not found: ") .. query)
+    jarvis.audio.play_not_found()
+    return { chain = false }
+end
+
+if not jarvis.fs.exists(match.path) then
+    jarvis.system.notify("Projects",
+        (lang == "ru" and "Путь не существует: " or "Path missing: ") .. match.path)
+    jarvis.audio.play_error()
+    return { chain = false }
+end
+
+local code_check = jarvis.system.exec("where code.cmd")
+if code_check.success and (code_check.stdout or ""):gsub("[\r\n]+$", "") ~= "" then
+    jarvis.system.exec(string.format('code "%s"', match.path))
+else
+    jarvis.system.open(match.path)
+end
+
+jarvis.system.notify(
+    lang == "ru" and "Проект" or "Project",
+    match.original_name .. "\n" .. match.path
+)
+jarvis.log("info", "opened project: " .. match.original_name .. " at " .. match.path)
+jarvis.audio.play_ok()
+return { chain = false }