feat: 添加本地命令支持，可在桌面端执行本地命令

[fengpanhe]

Local commands (local:) and global commands

Summary

• Add a local: command prefix so a folder command runs on the machine running the codeg desktop app instead of the folder's host. This lets a remote project launch local tools (e.g. open the remote dir in a local editor). No DB schema change and no server-side change — old remote codeg-server builds work as-is.
  • New desktop-only Tauri command run_local_command (src-tauri/src/commands/local_command.rs), registered in lib.rs, not exposed in the web router, so it can only ever run on the user's own machine. It spawns detached through the user's login shell ($SHELL -l -c 'eval "$CODEG_CMD"') with stdio nulled.
  • Injects CODEG_FOLDER_PATH (the folder's absolute path, remote path in remote mode) and CODEG_REMOTE_HOST (remote server host, empty for local projects).
  • Frontend: runLocalCommand in api.ts always uses the local shell transport; src/lib/local-command.ts parses the prefix and resolves the host; the command dropdown runs local: commands directly (no terminal tab) and shows an error in pure-web mode.
  • Example:
    • local: zed ssh://user@$CODEG_REMOTE_HOST$CODEG_FOLDER_PATH.
    • local: code --new-window --remote ssh-remote+devbox $CODEG_FOLDER_PATH
• Add global commands ("show in all folders"): a per-command toggle in the manage dialog. Global commands are stored in client localStorage (src/lib/global-commands.ts), use negative ids to stay distinct from DB primary keys, and show in every folder/worktree/remote connection with a 🌐 marker. This fixes commands disappearing when switching folders or worktrees (folder commands are keyed by folder_id, and every worktree is a separate folder).
• Fix: storedCommandId in terminal-context.tsx rejected ids < 0, so a running global command (negative id) read as "not running" after reload — now accepts any safe integer.
• i18n: new keys across all 10 languages (localUnavailable, localRunFailed, globalCommand, localCommandHint, globalLabel, globalHint).

Notes / risks

• Trust boundary: in remote mode the command list lives on the remote server; local: commands run on the user's machine only on an explicit click, never automatically.
• A local: command selected as a work_task preflight still runs on the remote host as-is — don't use it that way.
• Pure-web mode cannot run local commands (shows "desktop app only").

Test plan

• pnpm vitest run for affected suites — 36 files / 357 tests pass, including new local-command.test.ts, global-commands.test.ts, and extended command-dropdown.test.tsx (local exec, web refusal, global command runs in a folder with none of its own).
• tsc --noEmit, eslint, prettier --check — clean.
• cargo check (desktop) and cargo check --no-default-features --features server-bin — pass; local_command Rust unit tests pass (incl. a real spawn verifying both env vars).
• Manual: in a remote-desktop window, add local: <editor> "ssh://user@$CODEG_REMOTE_HOST$CODEG_FOLDER_PATH" and confirm it opens on the local machine.
• Manual: toggle "show in all folders", switch folders/worktrees, confirm the command persists.

Files

22 files, +707 / −24: backend 3 (new local_command.rs), frontend components 3, context 1, api.ts, 2 new libs (+2 tests), i18n 10.