Summary

Adds per-thread Codex args overrides as a composer control and applies effective args at runtime before thread start/resume/send.

The change keeps per-thread runtime behavior aligned with the selected profile without mutating workspace/global defaults.

The dropdown only renders when more than one args profile option exists (default + at least one configured override), so there is no extra composer noise for users without overrides.

Key Changes

• Composer + thread UX
  • Added per-thread Codex args selector to ComposerMetaBar.
  • Added a dedicated slider icon for Codex-args selection.
  • Added per-thread args badges in sidebar thread rows (regular + pinned lists).
• Thread-scoped state + no-thread seeding
  • Extended persisted ThreadCodexParams with codexArgsOverride.
  • Added and exported __no_thread__ scope support so pre-thread selections persist.
  • Wired codex args through pending new-thread seed flow so first message inherits composer selection.
• Runtime apply path (app + daemon parity)
  • Added set_workspace_runtime_codex_args end-to-end:
    • shared core: workspaces_core::set_workspace_runtime_codex_args_core
    • app command surface (src-tauri/src/workspaces/commands.rs, src-tauri/src/lib.rs)
    • daemon RPC surface (src-tauri/src/bin/codex_monitor_daemon.rs, rpc/workspace.rs)
    • remote allowlist (src-tauri/src/remote_backend/mod.rs)
    • frontend wrapper (src/services/tauri.ts)
  • Runtime args apply before:
    • startThread / workspace thread ensure
    • resumeThread on thread selection
    • turn/start send path
  • Steer path intentionally skips runtime apply.
• Args parsing/sanitization utilities
  • Added src/features/threads/utils/codexArgsProfiles.ts to parse/sanitize args and build user-facing labels/options.
  • Unsupported flags are filtered for per-thread runtime overrides; selection with ignored flags shows a warning toast.
  • Settings help text documents ignored flags.
• Post-review regression hardening
  • Thread selection resume no longer fails when runtime preflight sync errors; resume still proceeds.
  • Composer options now include the active selected override even when it no longer exists in app/workspace settings.
  • Thread badges now reflect sanitized/effective runtime args (ignored-only overrides no longer appear as active badges).

Behavior Notes

• Composer selection persists in no-thread scope and carries into first-thread creation.
• Thread-scoped override takes precedence when present.
• If thread-scoped params are missing, runtime apply falls back to no-thread scope.
• Explicit thread-scoped null still means “use resolved default args”.
• Backend runtime apply returns { appliedCodexArgs, respawned }.
• Runtime apply is a no-op when disconnected or when effective args are unchanged.

Test Coverage Added/Updated

• Added src/features/threads/utils/codexArgsProfiles.test.ts
• Added src/features/app/orchestration/useThreadOrchestration.test.ts
• Expanded src/features/threads/utils/threadCodexParamsSeed.test.ts for no-thread fallback + sanitization scenarios
• Expanded src/features/threads/hooks/useThreadMessaging.test.tsx for runtime-apply behavior and steer skip
• Expanded src/features/threads/hooks/useThreads.integration.test.tsx to assert runtime apply occurs before start/resume entry points
• Expanded src/features/threads/hooks/useThreads.integration.test.tsx to assert resume still occurs when runtime preflight fails
• Expanded src/features/threads/utils/codexArgsProfiles.test.ts for active-override option inclusion and effective badge behavior

Validation Run

• npm run typecheck
• npm run test -- src/features/threads/hooks/useThreads.integration.test.tsx src/features/threads/hooks/useThreadMessaging.test.tsx src/features/threads/utils/threadCodexParamsSeed.test.ts src/features/threads/hooks/useThreadCodexParams.test.tsx src/features/threads/utils/codexArgsProfiles.test.ts src/features/app/orchestration/useThreadOrchestration.test.ts
• npm run test
• cd src-tauri && cargo check
• cd src-tauri && cargo test set_workspace_runtime_codex_args --lib