feat(studio): differentiate web search and URL fetch in chat tool UI (#4802)

Differentiate web_search query searches from URL fetches in the Studio chat UI.

Backend (llama_cpp.py):
- Emit "Reading: hostname" for URL fetches and "Searching: query" for query searches in SSE status events
- Only show hostname for valid http/https URLs; schemeless/non-http URLs get "Reading page..." generic fallback
- Strip www. prefix for consistency with the frontend

Frontend (tool-ui-web-search.tsx):
- Tool card shows "Read hostname" / "Reading hostname..." for URL fetches
- Shows "Searched query" / "Searching for query..." for query searches
- Uses new URL() with protocol check; falls back to "Read page" / "Reading page..." for non-http URLs

studio/backend/core/inference/llama_cpp.py

@@ -22,6 +22,7 @@ import threading
 import time
 from pathlib import Path
 from typing import Generator, Optional
+from urllib.parse import urlparse
 
 import httpx
 
@@ -2270,7 +2271,7 @@ class LlamaCppBackend:
         Agentic loop: let the model call tools, execute them, and continue.
 
         Yields dicts with:
-          {"type": "status", "text": "Searching: ..."}   -- tool status updates
+          {"type": "status", "text": "Searching: ..."/"Reading: ..."}   -- tool status updates
           {"type": "content", "text": "token"}            -- streamed content tokens (cumulative)
           {"type": "reasoning", "text": "token"}          -- streamed reasoning tokens (cumulative)
         """
@@ -2837,7 +2838,18 @@ class LlamaCppBackend:
                         arguments = raw_args
 
                     if tool_name == "web_search":
-                        status_text = f"Searching: {arguments.get('query', '')}"
+                        _ws_url = (arguments.get("url") or "").strip()
+                        if _ws_url:
+                            _parsed = urlparse(_ws_url)
+                            if _parsed.scheme in ("http", "https") and _parsed.hostname:
+                                _ws_host = _parsed.hostname
+                                if _ws_host.startswith("www."):
+                                    _ws_host = _ws_host[4:]
+                                status_text = f"Reading: {_ws_host}"
+                            else:
+                                status_text = "Reading page..."
+                        else:
+                            status_text = f"Searching: {arguments.get('query', '')}"
                     elif tool_name == "python":
                         preview = (
                             (arguments.get("code") or "").strip().split("\n")[0][:60]

studio/frontend/src/components/assistant-ui/tool-ui-web-search.tsx

@@ -52,6 +52,18 @@ const WebSearchToolUIImpl: ToolCallMessagePartComponent = ({
   status,
 }) => {
   const query = (args as { query?: string })?.query ?? "";
+  const url = ((args as { url?: string })?.url ?? "").trim();
+  const isUrlFetch = !!url;
+  const displayDomain = (() => {
+    if (!url) return "";
+    try {
+      const parsed = new URL(url);
+      if (parsed.protocol !== "http:" && parsed.protocol !== "https:") return "";
+      return parsed.hostname.replace(/^www\./, "");
+    } catch {
+      return "";
+    }
+  })();
   const isRunning = status?.type === "running";
   const sources = result
     ? parseSearchResults(
@@ -75,7 +87,13 @@ const WebSearchToolUIImpl: ToolCallMessagePartComponent = ({
   return (
     <ToolFallbackRoot open={open} onOpenChange={setOpen}>
       <ToolFallbackTrigger
-        toolName={query ? `Searched "${query}"` : "Web Search"}
+        toolName={
+          isUrlFetch
+            ? displayDomain ? `Read ${displayDomain}` : "Read page"
+            : query
+              ? `Searched "${query}"`
+              : "Web Search"
+        }
         status={status}
         icon={GlobeIcon}
       />
@@ -83,7 +101,12 @@ const WebSearchToolUIImpl: ToolCallMessagePartComponent = ({
         {isRunning ? (
           <div className="flex items-center gap-2 text-sm text-muted-foreground">
             <LoaderIcon className="size-3.5 animate-spin" />
-            <span>Searching for &ldquo;{query}&rdquo;&hellip;</span>
+            <span>
+              {isUrlFetch
+                ? <>Reading {displayDomain || "page"}&hellip;</>
+                : <>Searching for &ldquo;{query}&rdquo;&hellip;</>
+              }
+            </span>
           </div>
         ) : sources.length > 0 ? (
           <div className="flex flex-wrap gap-1.5">