feat: add tool framework foundation (types, registry, executor, shell tool, model types, SOUL.md)

- Task 0: SOUL.md + loadSystemPrompt() in daemon
- Task 1: Tool type definitions (Tool, ToolCall, ToolResult, etc.)
- Task 2: ToolRegistry with Anthropic/OpenAI serialization
- Task 3: ToolExecutor with hooks, timeout, truncation
- Task 4: shell.exec builtin tool
- Task 8: Model types updated for tool use (ToolDefinition, ModelToolCall, etc.)
- Task 15: Model index exports for tool types

src/daemon/index.ts

@@ -8,7 +8,7 @@ import { SessionStore, SessionManager } from '../session/index.js';
 import { HookEngine } from '../hooks/index.js';
 import { resolve } from 'path';
 import { homedir } from 'os';
-import { mkdirSync } from 'fs';
+import { mkdirSync, readFileSync, existsSync } from 'fs';
 
 export interface DaemonContext {
   config: Config;
@@ -21,9 +21,22 @@ export interface DaemonContext {
   modelRouter: ModelRouter;
 }
 
-const SYSTEM_PROMPT = `You are Flynn, a helpful personal AI assistant. You are direct, concise, and helpful. You can help with a variety of tasks including answering questions, providing information, and having conversations.
+function loadSystemPrompt(): string {
+  // Try to load SOUL.md from working directory first, then from project root
+  const paths = [
+    resolve(process.cwd(), 'SOUL.md'),
+    resolve(import.meta.dirname, '../../SOUL.md'),
+  ];
 
-Keep responses focused and avoid unnecessary verbosity. Use markdown formatting when it improves readability.`;
+  for (const soulPath of paths) {
+    if (existsSync(soulPath)) {
+      return readFileSync(soulPath, 'utf-8');
+    }
+  }
+
+  // Fallback if SOUL.md not found
+  return 'You are Flynn, a helpful personal AI assistant. Be direct, concise, and helpful. Use markdown when it improves readability.';
+}
 
 function createModelRouter(config: Config): ModelRouter {
   const models = config.models;
@@ -117,7 +130,7 @@ export async function startDaemon(config: Config): Promise<DaemonContext> {
   // Initialize native agent with session
   const agent = new NativeAgent({
     modelClient: modelRouter,
-    systemPrompt: SYSTEM_PROMPT,
+    systemPrompt: loadSystemPrompt(),
     session,
   });