fix(chat): remove duplicate web_search tool in agentic_tools_all

agentic_tools_literal() already contains a custom web_search tool.
agentic_tools_with_web() adds the Anthropic server-side web_search_20250305
tool (also named web_search). Combining them caused Anthropic to reject
every agentic request with 'Tool names must be unique.'

agentic_tools_all() now calls agentic_tools_literal() directly. Connector
tools splice in as before. The web_search-only variant (agentic_tools_with_web)
is unchanged for callers that specifically want native search without connectors.

chat.el

@@ -317,10 +317,13 @@ fn connector_tools_json() -> String {
     return arr
 }
 
-// Built-in tools + native web_search + every connector tool, as one tools array.
-// Splices connector tools in before the closing bracket of the base array.
+// Built-in tools + every connector tool, as one tools array.
+// Uses agentic_tools_literal (not agentic_tools_with_web) to avoid a duplicate
+// "web_search" name — the literal already includes a custom web_search handler,
+// and adding the Anthropic server-side web_search_20250305 (same name) causes
+// Anthropic to reject with "Tool names must be unique."
 fn agentic_tools_all() -> String {
-    let base: String = agentic_tools_with_web()
+    let base: String = agentic_tools_literal()
     let conn: String = connector_tools_json()
     let conn_inner: String = str_slice(conn, 1, str_len(conn) - 1)
     if str_eq(conn_inner, "") {