Fix duplicate /clear in the slash command menu

A client command and a provider command can share a name (e.g. clear).
Both produced the same option id, which became a duplicate React key —
React then left stale rows and scrambled ordering, so /clear showed
twice and ranking broke as the query narrowed. Drop the colliding
provider command and keep the client one, which has extra affordances.

packages/app/src/hooks/use-agent-autocomplete.ts

@@ -318,13 +318,14 @@ export function useAgentAutocomplete(input: UseAgentAutocompleteInput): AgentAut
       const providerCommands = commands.map(
         (command): AvailableCommand => ({ source: "provider", command }),
       );
+      const clientCommandNames = new Set(CLIENT_SLASH_COMMANDS.map((command) => command.name));
       const availableCommands: AvailableCommand[] = isDraftContext
         ? providerCommands
         : [
             ...CLIENT_SLASH_COMMANDS.map(
               (command): AvailableCommand => ({ source: "client", command }),
             ),
-            ...providerCommands,
+            ...providerCommands.filter((entry) => !clientCommandNames.has(entry.command.name)),
           ];
       const matches = filterAndRankCommandAutocompleteEntries(
         availableCommands,