Change getAllTools() to return ToolInfo[] instead of string[]

Breaking change: pi.getAllTools() now returns Array<{ name, description }>
instead of string[]. Extensions needing just names can use .map(t => t.name).

Removes redundant getToolInfo() method added in original PR.

Fixes #647

packages/coding-agent/docs/extensions.md

@@ -887,6 +887,8 @@ Manage active tools.
 
 ```typescript
 const active = pi.getActiveTools();  // ["read", "bash", "edit", "write"]
+const all = pi.getAllTools();        // [{ name: "read", description: "Read file contents..." }, ...]
+const names = all.map(t => t.name);  // Just names if needed
 pi.setActiveTools(["read", "bash"]); // Switch to read-only
 ```