chore(cli-version): verify agy against 1.2.0

[kaizhou-lab]

Moves VERIFIED_AGY_VERSION from 1.1.28 to 1.2.0 — the first non-patch agy bump in this series.

Gate	Result
A — contract	DEGRADED — agy publishes no protocol schema; gate B carries the weight
B — live e2e	PASS 7/7, 141.76s
C — release notes	CLEAR

The minor version moves nothing we drive

Checked first, because that is what a minor bump warrants. --help and models --help are byte-identical 1.1.28 → 1.2.0, diffed against the captures stored with the previous record rather than by re-running the old binary (which would have self-updated it away). All nine flags build_argv emits are present.

Gate B ran against a manifest download whose sha512 was checked before it executed; the log reports only version=1.2.0, and the binary was byte-identical before and after (mtime=06:30:29 size=178935744). The machine's own agy stayed on 1.1.18.

Everything on our surface is a fix

• Content-safety-filtered prompts no longer fail with a spurious "no candidate found", end silently with an empty turn, or retry the rejected input — the CLI now surfaces a content-filter stop reason. "Ending silently with an empty turn" is the exact failure shape these gates keep turning up, so this removes a real class of it.
• Older conversations no longer fail to resume with unknown step type. We resume through --conversation, so this is directly our path.
• Third-party MCP tools whose input schemas omit additionalProperties no longer fail validation. Gate B drives an MCP tool call and it passed.
• The per-message filesystem customization discovery walk is gone — latency on our path.

The new stop reason is the only addition to the wire, and it cannot break us: wire.rs is tolerant by construction (its own header says so), the state enum carries #[serde(other)] Unknown, and we do not consume a stop-reason field at all — grepped, no stop_reason / finish_reason anywhere under backend/antigravity/.

Not our surface

remote-control start/status/stop as an OS-registered service, half-page scrolling and navigation.half_page_* keybindings, scratch/ files churning the artifact panel, plugin-bundled MCP initialisation, and the ERROR: logging before google.Init prefix in cli.log.

A grep trap worth knowing for this page

The web changelog interleaves Antigravity Hub releases (2.x, and 1.2x.y such as 1.21.6, 1.22.2) with CLI releases, so a bare 1\.[0-9]+\.[0-9]+ matches Hub entries and produced a nonsense "latest CLI" list on the first attempt. Anchor on the CLI-section link instead:

grep -oE 'View release [0-9]+\.[0-9]+\.[0-9]+' <page> | sed 's/View release //' | sort -u -V

Both sources carry 1.2.0 and agree.

Tests

The pinned older/newer pair moves to 1.1.29 / 1.2.1 rather than 1.1.27 / 1.1.29. That is deliberate: 1.1.29 vs 1.2.0 is exactly where a lexical compare gets the answer backwards, so the assertion now guards the component-wise comparison at the boundary that just became reachable. cargo test -p aionui-session --lib cli_version: 14/14. Clippy clean, fmt clean.

Record: ~/aion/protocols/samples/antigravity-cli/1.2.0/

Constants and record only — no source change.