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/models/index.ts

@@ -3,4 +3,18 @@ export { OpenAIClient, type OpenAIClientConfig } from './openai.js';
 export { OllamaClient, type OllamaClientConfig } from './local/index.js';
 export { LlamaCppClient, type LlamaCppClientConfig } from './local/index.js';
 export { ModelRouter, type ModelRouterConfig, type ModelTier } from './router.js';
-export type { Message, ChatRequest, ChatResponse, ModelClient } from './types.js';
+export type {
+  Message,
+  ChatRequest,
+  ChatResponse,
+  ChatStreamEvent,
+  TokenUsage,
+  ModelClient,
+  StreamingModelClient,
+  ToolDefinition,
+  ModelToolCall,
+  ContentBlock,
+  ToolResultEntry,
+  ToolMessage,
+  ConversationMessage,
+} from './types.js';