Verify Antigravity API-key ACP lane live

## Gap (found by finish 8812) Epic 8783's main new capability is PR #6573 (task 8810), which puts Antigravity API-key runs on ACP through agy_acp_server 1.4.1. It was never run live on dev. Task 8811 reported "Antigravity api_key (AC4 live api_key steps)" as untested because there was no dev account. It ran only the oauth lane, which stays legacy by design. The same run settled Gemini API-key ACP on dev (dev task 5231), so the Gmind org already has a Gemini API key the console accepts. Antigravity's API-key sign-in uses that same Gemini key type (agy authenticate `gemini-api-key`). Reproduction / observation: task 8811 settled_output and no_pr_evidence list "Untested (no dev account): ... Antigravity api_key". Jaah Deploy for 6e8fe9921 (and the later ad0f8f1ee) succeeded on dev, so the code is deployed but has not been tried. Cause: there is no Antigravity API-key account in the dev org. This is not a code defect. ## Fix (no new surface, no code) 1. On app.dev.jaah.ai, sign in as the operator (credential `jaah/debug/main/operator-login`). Act as Gmind, following the recipe mem-23382. 2. Through the console UI only (Machines › Brains / Settings › Accounts), add an Antigravity account with auth = API key. Use the Gemini API key the Gmind org already holds, or the one the operator supplies. If the key cannot be reused through the UI, ask the operator one `Credential` question. 3. Run the AC4 live steps for API key (below). Then remove the account, or leave it in place, and say which in the report. 4. If an existing Codex account can be added the same way, also run one Codex task. I2/I4 changed Codex's credential reads and rollout walk, and that lane is also untested on dev. Otherwise point to #8856. ## Acceptance - AC4-1: an Antigravity API-key task on project mr-6382-static settles → verify: task id and final state on the task page. - AC4-2: the Chat view streams normalised turns and tool calls → verify: a screenshot of the Chat view. - AC4-3: Audit › Sessions shows runtime ACP. Transcript and usage gaps are known pre-existing issues (#8858, #8859): note them, but they do not fail this check → verify: a screenshot of the Sessions row. - AC4-4: flip the Antigravity API-key ACP switch OFF in Settings › Providers, see a legacy launch, then restore it ON → verify: the two task ids. - A regression found → file one focused task naming the lane, the task ids and the evidence. Out of scope: no code edits and no PR. Do not touch the oauth lane (legacy by design, #8841) or the steer/MCP prefix work (#8842). Do not use a CLI, API or SQL against Jaah: console UI only. Do not redesign any page. Done means: - The report lists the dev task id, screenshots and a verdict for each AC4 step for Antigravity API key, plus the Codex result or a pointer to #8856. - The task settles `no_pr` (`no_code_needed`), with that per-step evidence.

Antigravity API-key ACP live check on dev not run. Blocked: no Gemini key was reusable (gem2 is write-only) and the operator chose to skip supplying one. The ACP switch was confirmed deployed and ON. Codex check deferred to #8856. No code. Memory: used mem-23382.