Add semantic search and analytics tools for sessions

Phase 7 complete: Advanced session analysis capabilities

New MCP Tools (3):
1. session_semantic_search - Vector similarity search across all sessions
2. session_productivity_analytics - Metrics (avg duration, tasks, commits, tokens)
3. session_pattern_detection - Detect patterns (tool usage, task types)

Features:
- Semantic search with embedding-based similarity
- Fallback to ILIKE text search if embeddings unavailable
- Analytics over configurable time periods (week/month/quarter)
- Pattern detection with frequency analysis

Use Cases:
- Find similar past work: "sessions about WhatsApp integration"
- Track productivity: avg commits/tasks per session
- Identify tool usage patterns: which tools used most often
- Analyze task type distribution

All 7 phases complete! System ready for testing.

Related: CF-257

Co-Authored-By: Claude Sonnet 4.5 <noreply@anthropic.com>

src/index.ts

@@ -59,6 +59,9 @@ import {
   projectDocGet,
   projectDocList,
   sessionDocumentationGenerate,
+  sessionSemanticSearch,
+  sessionProductivityAnalytics,
+  sessionPatternDetection,
 } from './tools/session-docs.js';
 
 // Create MCP server
@@ -562,6 +565,37 @@ server.setRequestHandler(CallToolRequestSchema, async (request) => {
           session_id: a.session_id,
         });
         break;
+      case 'session_semantic_search':
+        result = JSON.stringify(
+          await sessionSemanticSearch({
+            query: a.query,
+            project: a.project,
+            limit: a.limit,
+          }),
+          null,
+          2
+        );
+        break;
+      case 'session_productivity_analytics':
+        result = JSON.stringify(
+          await sessionProductivityAnalytics({
+            project: a.project,
+            time_period: a.time_period,
+          }),
+          null,
+          2
+        );
+        break;
+      case 'session_pattern_detection':
+        result = JSON.stringify(
+          await sessionPatternDetection({
+            project: a.project,
+            pattern_type: a.pattern_type,
+          }),
+          null,
+          2
+        );
+        break;
 
       default:
         throw new Error(`Unknown tool: ${name}`);