feat: add timeline-report skill with token economics, compress context output 53%

## Summary
- New timeline-report skill for generating narrative project history reports
- Compressed markdown context output ~53% (tables → flat compact lines, verbose labels → terse format)
- Added `full=true` param to /api/context/inject for fetching all observations
- Split TimelineRenderer into separate markdown/color rendering paths
- Removed arbitrary file write vulnerability (dump_to_file param)
- Fixed timestamp ditto marker leaking across session summary boundaries

## Review
- Rebased on main (v10.6.0) to preserve OpenClaw system prompt injection
- Reviewed by /review (gstack) + /octo:review (Codex, Gemini, Claude fleet)
- Security fix (dump_to_file removal) confirmed by all 3 reviewers
- Timestamp bug caught by Codex, fixed

🤖 Generated with [Claude Code](https://claude.com/claude-code)

src/services/worker/http/routes/SearchRoutes.ts

@@ -208,6 +208,7 @@ export class SearchRoutes extends BaseRouteHandler {
     // Support both legacy `project` and new `projects` parameter
     const projectsParam = (req.query.projects as string) || (req.query.project as string);
     const useColors = req.query.colors === 'true';
+    const full = req.query.full === 'true';
 
     if (!projectsParam) {
       this.badRequest(res, 'Project(s) parameter is required');
@@ -234,7 +235,8 @@ export class SearchRoutes extends BaseRouteHandler {
       {
         session_id: 'context-inject-' + Date.now(),
         cwd: cwd,
-        projects: projects
+        projects: projects,
+        full
       },
       useColors
     );