feat: add agent tools and sanitize tool names for Anthropic API

Add 8 new agent-callable tools (sessions.list/history/create/delete,
agents.list, message.send, cron.list/trigger) and sanitize tool names
at the API boundary (dots → underscores) to comply with Anthropic's
`^[a-zA-Z0-9_-]{1,128}` requirement. Reverse-maps sanitized names
back to internal names for hook callbacks and tool execution.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

src/tools/registry.test.ts

@@ -56,7 +56,7 @@ describe('ToolRegistry', () => {
 
     const anthropicTools = registry.toAnthropicFormat();
     expect(anthropicTools).toEqual([{
-      name: 'test.echo',
+      name: 'test_echo',
       description: 'Echoes input back',
       input_schema: echoTool.inputSchema,
     }]);
@@ -86,7 +86,7 @@ describe('ToolRegistry', () => {
     expect(openaiTools).toEqual([{
       type: 'function',
       function: {
-        name: 'test.echo',
+        name: 'test_echo',
         description: 'Echoes input back',
         parameters: echoTool.inputSchema,
       },
@@ -161,4 +161,37 @@ describe('ToolRegistry', () => {
       expect(() => reg.replace(makeTool('nonexistent'))).toThrow('not registered');
     });
   });
+
+  describe('ToolRegistry — API name sanitization', () => {
+    it('sanitizeToolName converts dots to underscores', () => {
+      expect(ToolRegistry.sanitizeToolName('shell.exec')).toBe('shell_exec');
+      expect(ToolRegistry.sanitizeToolName('file.read')).toBe('file_read');
+      expect(ToolRegistry.sanitizeToolName('no_dots')).toBe('no_dots');
+    });
+
+    it('getByApiName resolves sanitized names back to internal tools', () => {
+      const registry = new ToolRegistry();
+      registry.register(echoTool); // name is 'test.echo'
+
+      expect(registry.getByApiName('test_echo')).toBe(echoTool);
+      expect(registry.getByApiName('test.echo')).toBe(echoTool);
+      expect(registry.getByApiName('nonexistent')).toBeUndefined();
+    });
+
+    it('toAnthropicFormat outputs sanitized names', () => {
+      const registry = new ToolRegistry();
+      registry.register(echoTool);
+
+      const tools = registry.toAnthropicFormat();
+      expect(tools[0].name).toBe('test_echo');
+    });
+
+    it('toOpenAIFormat outputs sanitized names', () => {
+      const registry = new ToolRegistry();
+      registry.register(echoTool);
+
+      const tools = registry.toOpenAIFormat();
+      expect(tools[0].function.name).toBe('test_echo');
+    });
+  });
 });