feat(modes): introduced ACP mode for headless agent operation with session management and event streaming

- Added ACP (Agent Client Protocol) mode for headless agent operation via --mode acp flag.
- Integrated Agent Client Protocol SDK with session management, streaming communication, and event mapping.
- Added ensureOnDisk() method to SessionManager for immediate session persistence without requiring assistant messages.
- Changed session persistence to use atomic file rewrite for unflushed sessions.
- Implemented AcpAgent class with session management, prompt handling, MCP server configuration, and event streaming.

packages/coding-agent/package.json

@@ -40,6 +40,7 @@
 		"test": "bun test"
 	},
 	"dependencies": {
+		"@agentclientprotocol/sdk": "0.16.1",
 		"@mozilla/readability": "^0.6",
 		"@oh-my-pi/omp-stats": "workspace:*",
 		"@oh-my-pi/pi-agent-core": "workspace:*",
@@ -54,7 +55,8 @@
 		"diff": "^8.0",
 		"handlebars": "^4.7",
 		"linkedom": "^0.18",
-		"puppeteer": "^24.37"
+		"puppeteer": "^24.37",
+		"zod": "4.3.6"
 	},
 	"devDependencies": {
 		"@types/bun": "^1.3"