chore: switch texthooker-ui workflow to pnpm and add backlog tasks

backlog/tasks/task-73 - Consolidate-launcher-mpv-socket-readiness-primitives.md

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+---
+id: TASK-73
+title: Consolidate launcher mpv socket readiness primitives
+status: To Do
+assignee: []
+created_date: '2026-02-18 11:35'
+updated_date: '2026-02-18 11:35'
+labels:
+  - launcher
+  - mpv
+  - refactor
+dependencies: []
+priority: medium
+---
+
+## Description
+
+<!-- SECTION:DESCRIPTION:BEGIN -->
+Launcher contains multiple overlapping MPV readiness/polling helpers (`waitForSocket`, `waitForPathExists`, `waitForUnixSocketReady`) with mixed timeout/poll semantics. Consolidation needed for clarity and lower maintenance.
+<!-- SECTION:DESCRIPTION:END -->
+
+## Action Steps
+
+<!-- SECTION:PLAN:BEGIN -->
+1. Define one canonical socket readiness contract (existence + connectability + timeout).
+2. Replace duplicate polling helpers with a single implementation.
+3. Update all callsites (`mpv status`, idle launch flow, subtitle loading dependencies).
+4. Keep user-visible behavior and exit codes stable.
+5. Add focused tests for timeout and success/failure edge cases.
+<!-- SECTION:PLAN:END -->
+
+## Acceptance Criteria
+<!-- AC:BEGIN -->
+- [ ] #1 Single canonical MPV socket readiness helper remains
+- [ ] #2 All launcher callsites use unified helper
+- [ ] #3 Behavior/exit code compatibility maintained for CLI flows
+- [ ] #4 Test coverage added for readiness timeout behavior
+<!-- AC:END -->
+
+## Definition of Done
+<!-- DOD:BEGIN -->
+- [ ] #1 Launcher tests pass
+- [ ] #2 No dead helper functions remain
+<!-- DOD:END -->
+