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/services/worker-service.ts

@@ -7,7 +7,7 @@ import express, { Request, Response } from 'express';
 import { query } from '@anthropic-ai/claude-agent-sdk';
 import type { SDKUserMessage, SDKSystemMessage } from '@anthropic-ai/claude-agent-sdk';
 import { SessionStore } from './sqlite/SessionStore.js';
-import { buildInitPrompt, buildObservationPrompt, buildFinalizePrompt } from '../sdk/prompts.js';
+import { buildInitPrompt, buildObservationPrompt, buildSummaryPrompt } from '../sdk/prompts.js';
 import { parseObservations, parseSummary } from '../sdk/parser.js';
 import type { SDKSession } from '../sdk/prompts.js';
 import { logger } from '../utils/logger.js';
@@ -408,7 +408,7 @@ class WorkerService {
           db.close();
 
           if (dbSession) {
-            const summarizePrompt = buildFinalizePrompt(dbSession);
+            const summarizePrompt = buildSummaryPrompt(dbSession);
 
             logger.dataIn('SDK', `Summary prompt sent (${summarizePrompt.length} chars)`, {
               sessionId: session.sessionDbId,