fix(windows): tray notification copy, Claude Code disable modal, Claude Desktop 3P detection

[stuffbucket]

Three Windows-only fixes from hands-on testing of the v0.4.34/-beta builds. macOS is unaffected by all three (each change is platform-gated or touches only the Windows branch).

1. Startup notification copy + arrow (shell/src-tauri/src/lib.rs)

The "Maximal is running" toast pointed up at a menu bar that doesn't exist on Windows. Platform-gated the body:

• macOS: Look for the Maximal icon in your menu bar ↑ (unchanged)
• Windows/other: Maximal is running in your system tray ↓

2. "Restart Claude Code" modal on disable (AppCard.tsx + new platform.ts)

On Windows, a running Claude Code session keeps routing through the proxy until restarted (it reads its base URL at launch; macOS picks the change up live). Disabling the Claude Code toggle on Windows only now shows a modal (reusing the existing ConfirmDialog) telling the user to /exit and relaunch. Confirm proceeds; Cancel reverts the controlled switch. macOS and all other toggles are byte-for-byte unchanged. Closes #178.

3. Claude Desktop 3P dir + detection (claude-desktop-3p-config.ts, apps.ts)

Two bugs surfaced by an investigation of Anthropic's admin-deployment docs:

• Wrong drive: getClaude3pDir() wrote the 3P configLibrary to %APPDATA%\Claude-3p (Roaming), but Anthropic locates it under %LOCALAPPDATA%\Claude-3p (Local) — so the config landed where Claude Desktop never reads it. On macOS both halves share ~/Library/Application Support; on Windows the consumer config (Roaming) and the 3P dir (Local) diverge. Fixed to %LOCALAPPDATA%.
• Circular detection: the Apps route detected Claude Desktop via getClaude3pDir() existence — but that dir only exists after maximal writes it, so Claude read as not-installed until configured. Switched to the existing, already-tested claudeAppInstalled() (probes %LOCALAPPDATA%\AnthropicClaude + the WindowsApps\Claude.exe shim; /Applications/Claude.app on macOS — same as before).

Deferred (documented in memory, not blockers): Windows managed/enterprise config is registry-based (HKLM\SOFTWARE\Policies\Claude, managed > local) — we write only the local configLibrary (correct for unmanaged/dev); and MSIX/Store-build path virtualization under %LOCALAPPDATA%\Packages\Claude_pzs8sxrjxfjjc\… is not yet enumerated.

Validation

Full suite 1025 pass / 0 fail · check:fast clean · shell tsc clean · build:ui bundles. Test build cut as v0.4.35-beta.1 (prerelease, not Latest) for hands-on Windows verification of all four fixes (these three + the merged models-prime-on-sign-in #177).

Round 2 — second Windows test pass (fan-out investigation)

Three more issues from hands-on testing. macOS remains unaffected (each change is platform-gated, macOS-side, or Windows-only).

4. Claude Desktop MSIX/Store detection (configure-claude-desktop.ts)

The card still showed "Not installed" on a real Windows install. Root cause: the only candidates were the legacy Squirrel paths (%LOCALAPPDATA%\AnthropicClaude + the WindowsApps\Claude.exe alias). New Windows installs are MSIX/Store, which creates neither — they live under %LOCALAPPDATA%\Packages\Claude_<hash>. Added the known MSIX package dir as a candidate plus a Packages scan for the Claude_ / AnthropicPBC.Claude family prefix (hashed family names defeat any fixed path). macOS /Applications/Claude.app and the "can't tell → don't block" path on unknown platforms are untouched. 5 new injected-platform tests.

5. Splash render glitch on Windows (shell/src-tauri/src/lib.rs)

The transparent splash showed an empty outline for seconds before the brand fill appeared. Classic WebView2 cold-start: the native surface is presented before the compositor draws its first frame. Build the splash hidden and .show() it from on_page_load once the DOM reports Finished. macOS/WKWebView paints in lockstep so it fires immediately there — no regression.

6. Notification click → open Settings (shell/src-tauri/src/lib.rs)

• macOS: broadened the RunEvent::Reopen handler — clicking the "Maximal is running" banner (or the Dock icon) with no visible windows now opens Settings (account section when signed out, plain Settings otherwise).
• Windows: the installed tauri-plugin-notification (2.3.3) show() is fire-and-forget — no toast-activation callback exists on desktop at this version. Per maintainer decision, accepted as a limitation for now: tray left-click already opens Settings and the toast body points there. Making the Windows toast itself clickable would require direct tauri-winrt-notification activation (AUMID + COM) or a plugin swap — tracked as a follow-up, not in this PR.

Validation (round 2)

Full suite 1028 pass / 0 fail · lint clean · tsc clean · cargo check clean.