[idea] Add Muse (Muse Spark by Meta, dev.meta.ai) support

[ulises-jeremias]

Herdr currently detects ~21 agents (Pi, Claude Code, Codex, Cursor, etc.) via screen manifests and lifecycle hooks. Muse by Meta (Muse Spark) has no bundled detection, so it runs as Unknown and users must use HERDR_AGENT=muse workaround without rich working/blocked/idle state.

Idea / problem
Users running muse (binary installed via curl -fsSL https://dev.meta.ai/install.sh | bash → ~/.local/bin/muse, launcher https://api.meta.ai/muse-launcher.sh) inside Herdr see no agent-specific state. No muse.toml, no Agent::Muse registration, no muse in ALL/SCREEN_MANIFEST_AGENTS. Up to 1730 forks and 24k stars suggest many will try Muse as Meta's cheaper coding agent alternative (https://developer.meta.com/ai/products/muse-code/).

Requested change
Add first-class muse support mirroring existing screen-manifest agents (claude/codex/cursor):

• Register Agent::Muse (muse, muse-code, muse_code) in src/detect/mod.rs
• Add src/detect/manifests/muse.toml with idle/working/blocked rules (OSC title + bottom-buffer hints), versioned 2026.08.05.1
• Work strictly via screen-manifest initially (no lifecycle hook authority yet), like Claude/Codex

Why
Provides immediate sidebar rollups and herdr agent explain/agent wait for Muse without needing HERDR_AGENT wrapper, improves parallel workflow visibility, and unblocks later session-only hook if Muse adds one. Keeps detection evidence-based per AGENTS.md (capture via herdr agent read --source detection --format text/ansi).

Implementation ready
Prepared in fork ulises-jeremias/herdr branch feat/muse-support:

• Commit b8271ad1 feat: add Muse support (2 files: src/detect/mod.rs, src/detect/manifests/muse.toml)
• PR feat: add Muse support #2389 opened as draft (auto-closed by pr-gate because author not in APPROVED_CONTRIBUTORS — expected). Maintainer can reopen if this Discussion is approved.
• Manifest is conservative; can be refined live with herdr agent explain --json once approved.

Happy to address docs (docs/next/website/src/content/docs/agents.mdx) or add integration status once Muse exposes hooks.

Links: fork https://github.com/ulises-jeremias/herdr/tree/feat/muse-support — PR #2389 — launcher https://api.meta.ai/muse-launcher.sh

[ulises-jeremias]

Update: pushed docs polish to same branch — added Muse row to docs/next/website/src/content/docs/agents.mdx (screen manifest | none). Branch now 2 commits: b8271ad1 feat: add Muse support + 63480e87 docs: add Muse.... Ready for maintainer to reopen PR #2389 if approved. Live UI refinement pending due to Muse session lock RO fs in sandbox (need host run of muse --provider echo to capture bottom-buffer via herdr agent read).

[ulises-jeremias]

Update: fixed CI failure https://github.com/herdrdev/herdr/actions/runs/31054850901/job/92470014565 — E0004 non-exhaustive Some(Agent::Muse) in src/config/sound.rs:121.

Fix pushed ceeaf1ae:

• src/config/sound.rs: added muse: AgentSoundSetting field, Some(Agent::Muse) => self.muse arm + Default muse: Default
• src/config/sidebar.rs: added Agent::Muse to accepts_every_canonical_agent_override_key

Branch now 3 commits: a2d9f2b5 feat + 6f4e0086 docs + ceeaf1ae fix (all author ulises-jeremias <ulisescf.24@gmail.com>). Ready for CI re-run on reopen. PR #2389 head updated via force-push.