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>

src/sdk/worker.ts

@@ -17,7 +17,7 @@ import { query } from '@anthropic-ai/claude-agent-sdk';
 import type { SDKUserMessage, SDKSystemMessage } from '@anthropic-ai/claude-agent-sdk';
 import { SessionStore } from '../services/sqlite/SessionStore.js';
 import { getWorkerSocketPath } from '../shared/paths.js';
-import { buildInitPrompt, buildObservationPrompt, buildFinalizePrompt } from './prompts.js';
+import { buildInitPrompt, buildObservationPrompt, buildSummaryPrompt } from './prompts.js';
 import { parseObservations, parseSummary } from './parser.js';
 import type { SDKSession } from './prompts.js';
 
@@ -374,7 +374,7 @@ class SDKWorker {
           this.isFinalized = true;
           const session = await this.loadSession();
           if (session) {
-            const finalizePrompt = buildFinalizePrompt(session);
+            const finalizePrompt = buildSummaryPrompt(session);
             console.error('[claude-mem worker] Yielding finalize prompt to SDK agent', {
               sessionDbId: this.sessionDbId,
               sdkSessionId: this.sdkSessionId,