Summary

• New desktop/ Tauri shell that drives a reasonix desktop JSON-RPC subcommand over stdio. Each tab owns an independent CacheFirstLoop, workspace, session, and file/symbol index — two projects can stream in parallel without blocking each other or crossing approvals.
• Extracts buildCodeToolset into src/code/setup.ts so the desktop and the code command share an identical tool surface. Wires web_search / web_fetch and run_skill (with subagent runner) on the way through — both were exported but never registered.
• pauseGate confirm / choice / plan routing uses AsyncLocalStorage to attribute requests to the tab whose async chain is currently running, so concurrent shell prompts can't land in the wrong tab.
• CacheFirstLoop._turn advances past loaded assistant messages on resume — the frontend's turn-keyed message map would otherwise treat a fresh response as a duplicate of an historical turn and route deltas into the old bubble.
• Release workflow builds Tauri bundles for linux-x64, macos-arm64, macos-x64, windows-x64 on tag push. Signing keys flow through env (Apple notary, Windows Authenticode, Tauri updater); details in desktop/SIGNING.md.

What's in the desktop client

• Multi-tab: Ctrl+T new, Ctrl+W close, Ctrl+Tab / Ctrl+Shift+Tab switch. Inactive tabs stay mounted (display: none) so they keep receiving streaming events.
• Workspace switcher: clickable pill in the Header opens a dropdown with current + recent (cap 8, persisted) + Pick-another-folder via Tauri dialog plugin.
• Sessions: backend mints desktop-<timestamp>-<tabIdx> per tab, writes meta.workspace for filtering. Click in sidebar to resume — runtime rebuilds with the picked session, meta.totalCostUsd / cacheHitTokens carryover seeded into the frontend's usage.
• @-mentions: file picker with preview (head 12 lines), @dir/ directory browse, @symbol exported-name search, recently-used promotion.
• Settings panel: API key (editable), workspace, preset (auto/flash/pro), reasoning effort, edit mode, budget cap, base URL, theme (dark/light), currency (CNY/USD), editor command.
• Editor open: clicking a file pill / path link invokes a custom open_in_editor Tauri command that spawns the configured editor (code, cursor, windsurf, ...) through cmd /c on Windows so .cmd shims resolve. Falls back to OS default when no editor is set. Line jump via -g path:line when the editor supports it.
• Streaming polish: rAF-batched per-tab delta dispatch, blinking caret block on the last live segment, ThinkingBar with integrated Stop button, Esc as global abort.

Test plan

• npm run verify clean
• cd desktop && npm run tauri dev boots, shows the whale empty state
• Single turn streams to completion; tool calls render with file pills
• @ opens picker, preview pane renders head of selected file
• @src/ lists files + folders in src; picking a folder re-queries
• Click sidebar session → history renders, send a new message → fresh assistant bubble streams (not appended to historical one)
• Ctrl+T opens second tab, point at a different workspace; turn A and turn B stream concurrently; shell-approval modals land in the originating tab
• Pick VS Code editor in Settings, click src/foo.ts:42 in agent output → opens in VS Code at line 42
• Tag-push triggers .github/workflows/release.yml (or workflow_dispatch with a tag) and produces installers per platform