fix(hub,web): query Codex models via machine RPC instead of session cwd (#1186)

SessionChat fetched Codex models through the session-scoped endpoint,
so the CLI listed models in the session process cwd, where a missing
directory or project-level Codex config could skew or break the result.
Use the machine-scoped endpoint (already used by NewSession) and drop
the now-unused session route and RPC plumbing.

Fixes #1072

web/src/api/client.ts

@@ -653,12 +653,6 @@ export class ApiClient {
         )
     }
 
-    async getSessionCodexModels(sessionId: string): Promise<CodexModelsResponse> {
-        return await this.request<CodexModelsResponse>(
-            `/api/sessions/${encodeURIComponent(sessionId)}/codex-models`
-        )
-    }
-
     async getSessionOpencodeModels(sessionId: string): Promise<OpencodeModelsResponse> {
         return await this.request<OpencodeModelsResponse>(
             `/api/sessions/${encodeURIComponent(sessionId)}/opencode-models`