feat(provider): merge upstream #11258 beta Muse Code support

[devin-ai-integration]

What Changed

Merges upstream pingdotgg/t3code#11258 (codex/muse-code-provider, beta Muse Code provider via @muse-code/sdk) into this fork's main as a single merge commit. The upstream branch was 155 commits behind main; four conflicts were resolved:

• apps/server/src/provider/Layers/ProviderService.ts — kept main's newer agentAccessSettings/project-settings routing and the Claude background-turn cursor persistence, plus Muse's forked-session cursor handling.
• apps/web/src/connection/storage.test.ts — kept both main's GitHub routing permission tests and Muse's thread snapshot cache tests.
• packages/contracts/src/settings.test.ts — kept main's default-permission tests and Muse's provider-settings tests.
• pnpm-lock.yaml — took main's lockfile and regenerated with vp i (adds @muse-code/sdk@0.1.1).

Why

Bring native Muse Code support into the fork. Upstream pingdotgg#11258 targets main directly, unlike pingdotgg#11392 which is built on the unmerged orchestration-v2 branch (pingdotgg#2829).

Verification

• Typecheck: server, web, contracts pass.
• Focused tests: server Muse + ProviderService (8 files, 206 tests), web storage.test.ts (6), contracts settings.test.ts (130) all pass.
• No browser/desktop/mobile pass done.

Checklist

• This PR is small and focused (it's an upstream merge, ~9k lines)
• I explained what changed and why
• I included before/after screenshots for any UI changes (see upstream PR)
• I included a video for animation/interaction changes (n/a)

Link to Devin session: https://app.devin.ai/sessions/0da2d13b759845ae99a28d2baabf5d7c
Open in Devin Desktop: https://app.devin.ai/desktop/session/0da2d13b759845ae99a28d2baabf5d7c?variant=devin
Requested by: @aminamos

[devin-ai-integration]

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[devin-ai-integration]

Completed recorded local web verification of 412bedfda.

Muse settings: verified; new-thread setup issue found

• PASS: Muse Code is Beta and disabled by default.
• PASS: Enabling without the CLI shows Not found, install/muse login guidance, and 0 models.
• PASS: Refresh, reload persistence, and repeated on/off toggles; no console errors or uncaught page exceptions.
• FAIL: New thread offers no Muse picker, says "Enable a provider," and its setup button opens disabled Antigravity rather than Muse.
• Not tested by request: installed-CLI model discovery and real turns. No Muse CLI installed.

Default disabled	Enabled / missing CLI

New-thread fallback	Setup opens Antigravity

Environment caveat

Original Chrome 133 rendered the provider list black. The unchanged app rendered correctly in Chrome 153, which was used for the completed flow. Original checkout's unrelated conflicted merge was preserved by testing a sibling worktree.

Devin session