feat(server): bump Antigravity ACP agent to 1.3.0

[Droyder7]

Problem

The Antigravity ACP agent binary was pinned to 1.1.1 (agy_acp_server_1.1.1), which lacked Intel Mac (darwin-x86_64) binary support (resolving to null) and was out of date with upstream official ACP registry PR #647.

Change

• Bump ANTIGRAVITY_RELEASE_VERSION to "1.3.0", matching the version string reported by the binary during the initialize handshake (agentInfo.version).
• Update official download URLs to the new pattern (agy-acp-server-1.3.0-<platform>.zip).
• Add support for Intel Macs (darwin-x64 mapped to agy-acp-server-1.3.0-darwin-x86_64.zip), bringing total supported platforms to 6 (darwin-arm64, darwin-x64, linux-x64, linux-arm64, win32-x64, win32-arm64).
• Update SHA-256 hashes and file sizes for all 6 release archives and extracted binaries (agy_acp_server and localharness_external).
• Update registry commit reference to dc55a34900fdd60e5e97c1cbd7825c5a1df673fc.
• Add test coverage in AntigravityInstallation.test.ts verifying all 6 platforms resolve valid assets.

This is PR 1 (base layer) of the 2-PR stack for Antigravity elicitation and multi-select support.

Side-Effects & Compatibility Analysis

• Platform Parity: Intel Mac (darwin-x64) was previously unsupported (returning null and failing with a platform unsupported message). It is now on full parity with Apple Silicon, Linux, and Windows.
• Managed Version Transitions: Runtime management resolves active binaries via managedDirectory/active.json pointing to versions/<releaseSha256>. Upgrading to 1.3.0 does not mutate or corrupt existing 1.2.6 runtime directories or active sessions.
• Verification Handshake: The 1.3.0 release satisfies all 5 mandatory installation verification constraints (protocolVersion: 1 | 2, loadSession: true, sessionCapabilities.resume, auth.logout, and oauth-personal auth method).
• Credentials & Session Compatibility: Existing sessions and OAuth tokens saved under oauth-personal remain fully compatible.

Scope and approval

• Resolves part of [Bug]: Antigravity ACP agent cannot use native elicitation or multi-select questions #15743.
• Focuses strictly on the provider binary release update and platform asset resolution, adhering to the one-problem rule in CONTRIBUTING.md.

Verification

• Verified the live binary startup handshake (initialize) with 1.3.0: confirmed protocol version 2, agentInfo.version: "1.3.0", loadSession: true, sessionCapabilities.resume, and oauth-personal auth methods.
• Verified archive contents and byte sizes across all 6 platform archives downloaded directly from dl.google.com.
• Ran focused unit test suites:
  • pnpm vp test run apps/server/src/provider/AntigravityInstallation.test.ts (33/33 passed).
  • pnpm vp test run apps/server/src/provider/acp/AntigravityAcpSupport.test.ts (37/37 passed).
  • pnpm vp check apps/server/src/provider/AntigravityInstallation.test.ts apps/server/src/provider/antigravityRelease.ts (passed cleanly).

[macroscopeapp]

Approvability

Verdict: Not approved

Macroscope's review found this PR not approvable — The PR changes the managed Antigravity runtime used for future installations across all supported platforms and adds Intel Mac support, altering production behavior and introducing a new platform path. The updated external binaries and release metadata warrant human verification beyond the focused resolution tests.

Notes:

• Diff unchanged. Approvability was decided on eligibility alone.

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ℹ️ Recent review info

⚙️ Run configuration

• Configuration used: Repository: pingdotgg/t3code/.coderabbit.yaml
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📥 Commits

Reviewing files that changed from the base of the PR and between 4ee6bfd and 2b1a4be.

📒 Files selected for processing (2)

• apps/server/src/provider/AntigravityInstallation.test.ts
• apps/server/src/provider/antigravityRelease.ts

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📝 Walkthrough

Walkthrough

The Antigravity release registry now uses version 1.3.0 assets for supported platforms and includes macOS x64. Tests verify asset resolution for macOS, Linux, and Windows architectures, and verify that FreeBSD x64 is unsupported.

Changes

Antigravity release assets

Layer / File(s)	Summary
Release registry and resolution tests apps/server/src/provider/antigravityRelease.ts, apps/server/src/provider/AntigravityInstallation.test.ts	The registry uses version 1.3.0 URLs, hashes, and size metadata for macOS, Linux, and Windows assets, and adds macOS x64. Tests check resolution for supported platforms and rejection of FreeBSD x64.

Priority: ⬇️ Low

Estimated code review effort: 2 (Simple) | ~10 minutes

Change: Feature

Suggested reviewers: juliusmarminge

Merge Risk: ⚪ Minimal · up to 2b1a4

The updated catalog includes the Intel Mac asset and matches the published 1.3.0 artifacts; no concrete installation or integrity risk remains in the reviewed change.

Security Architecture Review

Security architecture risk: 🔵 Low · up to 2b1a4

The update retains pinned downloads, executable validation, and staged activation. No introduced boundary weakness was identified, but the internal security behavior of the new third-party executable has not been assessed.

Retained concerns
No architecture-level concerns identified.

Security review details

Security Blast Radius

• inferred — The release change affects hosts installing the managed Antigravity provider through the default catalog, newly including Intel Macs. Its relevant security scope is the downloaded executable and harness operating within the existing provider launch context; no new launch authority is evidenced by the changed catalog.

Trust Boundaries and Controls

• observed — Downloaded bytes cross into executable installation only after pinned archive length and SHA-256 verification, archive-member restrictions, path and file-type checks, expected member sizes, and runtime identity validation. These controls constrain substitution and unsafe extraction but do not establish the upstream executable's internal security properties.

Resilience and Maintainability Implications

• observed — The installer serializes installation operations, shares concurrent starts, scopes temporary resources for cancellation cleanup, and uses leases to protect releases used by running sessions. Existing tests exercise validation failures, storage failures, cancellation, failed pointer publication, and retry, supporting containment of partially installed releases.

🚥 Pre-merge checks | ✅ 5

✅ Passed checks (5 passed)

Check name	Status	Explanation
Docstring Coverage	✅ Passed	No functions found in the changed files to evaluate docstring coverage. Skipping docstring coverage check. Docstring coverage is scoped to functions touched by this diff. Analyzed 0 functions across 2…
Linked Issues check	✅ Passed	Check skipped because no linked issues were found for this pull request.
Out of Scope Changes check	✅ Passed	Check skipped because no linked issues were found for this pull request.
Title check	✅ Passed	The title clearly and concisely describes the Antigravity ACP agent version update to 1.3.0.
Description check	✅ Passed	The description covers the problem, changes, scope and approval, and verification. It includes the relevant issue and specific test results.

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[Droyder7]

Gentle nudge — this is the prerequisite for #15926 (stacked on this branch). Merging this first keeps #15926's diff clean. If it's easier to review that one first, that works too: the bump rides along there and this PR can be closed as a no-op.