Refactor summary generation from session-level to request-level

Changed summary prompts to generate discrete per-request summaries instead of cumulative session summaries. This provides better chronological memory where each summary is a clean unit representing one request/response cycle.

Changes:
- Renamed buildFinalizePrompt() to buildSummaryPrompt() in src/sdk/prompts.ts
- Updated prompt text to focus on "THIS REQUEST" rather than "this session"
- Updated all import and function call sites in worker-service.ts and worker.ts
- Added IMPORTANT warning to emphasize request-level scope

Expected behavior: Each summary will now describe only what happened during that specific request, eliminating cumulative recaps.

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

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

plugin/scripts/search-server.js

@@ -265,6 +265,14 @@ ${e.stack}`:e.message;if(Array.isArray(e))return`[${e.length} items]`;let t=Obje
       WHERE project = ?
       ORDER BY created_at_epoch DESC
       LIMIT ?
+    `).all(e,t)}getRecentSummariesWithSessionInfo(e,t=3){return this.db.prepare(`
+      SELECT
+        sdk_session_id, request, learned, completed, next_steps,
+        prompt_number, created_at
+      FROM session_summaries
+      WHERE project = ?
+      ORDER BY created_at_epoch DESC
+      LIMIT ?
     `).all(e,t)}getRecentObservations(e,t=20){return this.db.prepare(`
       SELECT type, text, prompt_number, created_at
       FROM observations