feat: implement Undo/Redo/Timeline and Fork Features and fixed opencode.json reading issue on broken json (#99)

* feat: add /undo, /redo, /timeline slash commands and fork button

- Add /undo command to revert to previous user message
- Add /redo command to redo previously undone messages
- Add /timeline command to show conversation history
- Add fork button on user messages (hover) to create new session
- Add TimelineDialog component for navigating conversation history
- Show undo/redo/timeline in autocomplete when session exists
- Fix fork to use SDK session.fork API
- Silent no-op behavior for undo/redo when no messages (matches OpenCode CLI)

* fix: correct fork session endpoint and session switching

- Add hybrid SDK approach using v1 for existing methods and v2 for fork only
- v2 SDK has correct endpoint /session/{sessionID}/fork instead of broken /session/{id}/fork
- Fix forkFromMessage to use setCurrentSession instead of direct set
- Ensures both useSessionStore and useSessionManagementStore are consistent
- Fixes issue where forked sessions appeared empty until sending a new message

* fix: use direct fetch for fork to avoid v2 SDK build errors

- Remove v2 SDK imports and hybrid SDK approach
- Use direct fetch() call to /api/session/{sessionID}/fork endpoint
- Avoids type conflicts between v1 and v2 SDK
- Bypasses broken v1 SDK fork endpoint (wrong path parameter)
- All codebase now uses v1 SDK consistently

* fix: use jsonc-parser for config file parsing

- Replace strip-json-comments + JSON.parse with jsonc-parser
- Handles comments, trailing commas, and unquoted keys
- Matches OpenCode CLI config parsing behavior
- Fixes SyntaxError when reading global opencode.json config

* feat: improve timeline dialog with loading state and search

- Add loading spinner on fork button during operation (~30s on big sessions)
- Refresh session list after fork so new session appears in sidebar immediately
- Add search bar to filter messages by prompt text content
- Show 'No messages found' when search has no results
- Disable fork button while forking to prevent duplicate operations

AGENTS.md

@@ -113,6 +113,7 @@ SDK-managed SSE with AsyncGenerator, temp->real session ID swap (optimistic UI),
 - Run `bun run lint` and `bun run type-check` before finalizing changes
 - Adding `eslint-disable` requires justification in a comment explaining why typing is impossible
 - Do **not** use `any` or `unknown` casts as escape hatches; build narrow adapter interfaces instead
+
 - Refactors or new features must keep existing lint/type baselines green
 
 ### Theme Integration
@@ -128,6 +129,7 @@ SDK-managed SSE with AsyncGenerator, temp->real session ID swap (optimistic UI),
 - **Functional components**: Exclusive use of function components with hooks
 - **Custom hooks**: Extract logic for reusability
 - **Type-first development**: Comprehensive TypeScript usage
+- opencode repo is in ../opencode dir from this pwd dir check the codebase for any api undersatning . dont change opencode dir . 
 - **Component composition**: Prefer composition over inheritance
 
 ## Feature Implementation Map