feat: Add search skill with progressive disclosure and refactor existing skills

Enhancements:
- Added search skill with 10 HTTP API endpoints for memory queries
- Refactored version-bump and troubleshoot skills using progressive disclosure pattern
- Added operations/ subdirectories for detailed skill documentation
- Updated CLAUDE.md with skill-based search architecture
- Enhanced worker service with search API endpoints
- Updated CHANGELOG.md with v5.4.0 migration details

Technical changes:
- New plugin/skills/search/ directory with SKILL.md
- New .claude/skills/version-bump/operations/ (workflow.md, scenarios.md)
- New plugin/skills/troubleshoot/operations/ (common-issues.md, worker.md)
- Modified src/services/worker-service.ts (added search endpoints)
- Modified plugin/scripts/worker-service.cjs (rebuilt with search API)
- Reduced main skill files by 89% using progressive disclosure
- Token savings: ~2,250 tokens per session start

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

Co-Authored-By: Claude <noreply@anthropic.com>

plugin/skills/search/operations/recent-context.md

@@ -0,0 +1,93 @@
+# Get Recent Context
+
+Get recent session summaries and observations for a project.
+
+## When to Use
+
+- User asks: "What did we do last session?"
+- User asks: "What have we been working on?"
+- Need to understand recent project activity
+
+## Command
+
+```bash
+curl -s "http://localhost:37777/api/context/recent?project=claude-mem&limit=3"
+```
+
+## Parameters
+
+- **project**: Project name (default: current directory basename)
+- **limit**: Number of recent sessions (default: 3, max: 10)
+
+## Response Structure
+
+Returns complete session data including summaries, observations, and status:
+
+```json
+{
+  "project": "claude-mem",
+  "limit": 3,
+  "count": 3,
+  "sessions": [
+    {
+      "sdk_session_id": "abc-123",
+      "status": "completed",
+      "has_summary": 1,
+      "summary": {
+        "request": "Add authentication",
+        "completed": "Implemented JWT auth...",
+        "learned": "...",
+        "next_steps": "..."
+      },
+      "observations": [...]
+    }
+  ]
+}
+```
+
+## Use Case: "What did we do last session?"
+
+```bash
+# Get last 3 sessions
+RESULT=$(curl -s "http://localhost:37777/api/context/recent?limit=3")
+
+# Parse and format:
+# - Show session request
+# - Show what was completed
+# - List key observations
+# - Highlight next steps
+```
+
+## How to Present Results
+
+```markdown
+## Recent Work on claude-mem
+
+### Session 1 (Nov 9, 2024 - Completed)
+**Request:** Add user authentication
+
+**Completed:**
+- Implemented JWT authentication with token-based auth
+- Added middleware for route protection
+- Created login and refresh token endpoints
+
+**Key Observations:**
+1. 🟣 Implemented JWT authentication (#1234)
+2. 🔴 Fixed token expiration edge case (#1235)
+
+**Next Steps:**
+- Add password reset functionality
+- Implement rate limiting
+
+---
+
+### Session 2 (Nov 8, 2024 - Completed)
+...
+```
+
+## Tips
+
+1. This is the best operation for "what did we do recently" questions
+2. Returns complete context including summaries and observations
+3. Active sessions show current work in progress
+4. Default limit=3 is usually sufficient for recent context