perf: Optimize FrankenPHP/Octane configuration for high load

**Changes:**

1. **Caddyfile**:
   - Reduced num_threads from 24 to 20
   - Added request timeouts (read_body: 10s, write: 60s, idle: 120s)
   - With 4 containers: 20 × 4 = 80 total workers

2. **Dockerfile**:
   - Added explicit --workers=20 to octane:frankenphp command
   - Increased --max-requests from 250 to 1000
   - Applied to app-dev, app-release, and app stages

3. **Octane config**:
   - Enabled DisconnectFromDatabases listener
   - Enabled CollectGarbage listener
   - Prevents DB connection leaks and memory leaks

**Impact:**
- Better resource management under load
- Prevents connection pool exhaustion
- Requires db.t3.large (591 max connections) or better
- Supports up to 250 concurrent VUs

**Related:**
- Requires RDS upgrade from db.t4g.micro to db.t3.large
- Works with DB_CONNECTION_POOL_SIZE=25 (100 total connections)
- See configuration-analysis.md for details

Caddyfile

@@ -1,6 +1,9 @@
 {
 	frankenphp {
-		num_threads 24
+		# Reduced from 24 to 20 for better resource management
+		# With 4 containers: 20 × 4 = 80 total workers
+		# Requires db.t3.large (591 max connections) or better
+		num_threads 20
 	}
 	order php_server before file_server
 }
@@ -8,6 +11,15 @@
 http://:8000 {
 	root * /fleetbase/api/public
 	encode zstd br gzip
+	
+	# Request timeouts to prevent hanging
+	timeouts {
+		read_body 10s
+		read_header 5s
+		write 60s
+		idle 120s
+	}
+	
 	php_server {
 		resolve_root_symlink
 	}