fix: tools/list handler now returns proper tool metadata

Issue: The registerTool method was receiving description and inputSchema
parameters but marking them as unused (_description, _inputSchema) and
not storing them with the handler. This caused tools/list to return
tools without their description and inputSchema properties.

Fix: Remove underscore prefixes and explicitly set these properties on
the handler object before storing it in the tools Map.

Now tools/list will properly return:
- name: Tool name
- description: Tool description (from registerTool call)
- inputSchema: Tool input schema (from registerTool call)

This ensures MCP clients can see proper tool documentation and schemas.

Files changed:
- src/server.ts: Fixed registerTool to preserve metadata

Build: ✅ 0 errors

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

src/server.ts

@@ -42,10 +42,14 @@ export class ObsidianMCPServer {
    */
   registerTool(
     name: string,
-    _description: string,
-    _inputSchema: Record<string, unknown>,
+    description: string,
+    inputSchema: Record<string, unknown>,
     handler: ToolHandler
   ): void {
+    // Ensure handler has description and inputSchema
+    handler.description = description;
+    handler.inputSchema = inputSchema;
+    
     this.tools.set(name, handler);
     logger.debug('Registered tool', { name });
   }