Add chat session title persistence (codex)

[numnx]

🧩 Task: Add chat session title persistence

Automated task PR opened by Code UX for T01.

📋 Summary

Sprint: Sprint 151 · Menu Selects & Chat Session Title · Task: T01

Add chat session title generation/editing, constrain header selector menus while removing the All Sprints option, and add a Jira importer Hide in Work checkbox with tests and documentation.

📝 Full Task Prompt

## Objective
Add backend support for chat session titles so the first user message creates a concise title, persists it in `session-title.md`, and future chat prompts instruct the assistant to refresh it every 20 invocations.

## Scope
- `src/contracts/connection-chat-types.ts`
- `src/repositories/connection-chat-repository.ts`
- `src/repositories/connection-chat/conversation-query-utils.ts`
- `src/server/conversation-routes.ts`
- `src/server/request-parsers.ts`
- `src/services/chat-thread-runtime-service.ts`
- `src/services/chat-reply-prompt.ts`
- `tests/backend/repositories/connection-chat-repository.test.ts`
- `tests/backend/server/dashboard-chat-api.test.ts`
- `tests/backend/services/chat-thread-runtime-service.test.ts`

## Implementation Requirements
1. Extend `UpdateConversationThreadInput` so a thread title can be patched through `PATCH /api/conversations/threads/:threadId`, validate a non-empty trimmed title, and keep existing connection/runtime-state updates working.
2. Add a title helper for chat sessions that derives a maximum 8-word title from the first dashboard user message, strips markdown/control text, falls back to the existing timestamp title only when the first message has no useful words, and stores that title in `conversation_threads.title`.
3. Persist the generated or manually updated title to a project-local `.code-ux` file named `session-title.md` under a deterministic thread-specific location, creating parent directories as needed and avoiding writes outside the project directory.
4. Update `ChatThreadRuntimeService.postMessage` so newly created chat threads generate and persist the title from the first message, while existing threads keep their current title unless explicitly patched.
5. Update `buildChatReplayPrompt`/chat prompt assembly to include the current thread title and an instruction that `session-title.md` should be updated on the first message and every 20 chat invocations with an 8-word maximum descriptive title.
6. Add backend tests for first-message title generation, max-word truncation, manual title update via the API, file persistence, and unchanged behavior for runtime-state/route updates.

## Constraints
- Do not add a database migration unless a new column is truly required; prefer the existing `conversation_threads.title` field.
- Do not overwrite a user-edited title during later normal message sends.
- Keep hidden/internal messages from driving user-facing title generation.
- Preserve existing realtime thread update events when a title changes.
- Keep path handling cross-platform and prevent path traversal outside the project `.code-ux` directory.

## Verification
- `pnpm run test:backend -- tests/backend/repositories/connection-chat-repository.test.ts tests/backend/server/dashboard-chat-api.test.ts tests/backend/services/chat-thread-runtime-service.test.ts`
- `pnpm run lint`
- Success means new threads receive an 8-word-or-less title, title patches update DB and `session-title.md`, and existing chat route/runtime tests still pass.

✅ QA Review

⏳ QA review runs after this PR is opened. Check the task card in the dashboard for the outcome once it lands.

🤖 Model & Provider

Provider	Codex CLI
Model	gpt-5.5

⏱️ Timing

Started	2026-07-07 01:15:37 UTC
Finished	2026-07-07 01:22:24 UTC
Duration	6m 47s

📊 Token Usage

Metric	Value
Input tokens	125,987
Cached input tokens	2,586,752
Output tokens	13,394
Total tokens	2,726,133
Invocations	1
Tool calls	65
Active time	6m 17s

Included usage estimate (subscription/local login): $2.33

🌿 Branch Info

Base: feature/CODUX-151-menu-selects-chat-session-title
Head: task/feature-codux-151-menu-selects-chat-session-titl-t01-codex-mr9yjcrv

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🤖 Generated by Code UX