feat!: make web search Exa-only

BREAKING CHANGE: remove Tavily, Firecrawl, provider fallback,
and web-search-config. web_search and web_fetch now use
Exa-shaped inputs and return raw Exa-style details.

index.ts

@@ -1,5 +1,4 @@
 import type { ExtensionAPI } from "@mariozechner/pi-coding-agent";
-import { registerWebSearchConfigCommand } from "./src/commands/web-search-config.ts";
 import { createWebSearchRuntime } from "./src/runtime.ts";
 import { createWebFetchTool } from "./src/tools/web-fetch.ts";
 import { createWebSearchTool } from "./src/tools/web-search.ts";
@@ -9,5 +8,4 @@ export default function webSearch(pi: ExtensionAPI) {
 
   pi.registerTool(createWebSearchTool({ executeSearch: runtime.search }));
   pi.registerTool(createWebFetchTool({ executeFetch: runtime.fetch }));
-  registerWebSearchConfigCommand(pi);
 }