[Sun-GLiang]

Summary

Images can outlive their temporary sources, but the existing receive queue is in memory and message completion does not guarantee image persistence. Structured ACP image results also need durable publication and ordered mixed content. Make Host-owned image reception recoverable and distinguish reception, saved originals, preview limits and actual failures.

• Publish ACP image/resource output through the shared Host image-delivery service. Persist Artifact references rather than base64 in canonical events; preserve ordered text/image/diff blocks and accepted output during cancellation or transport loss.
• Persist reception jobs and bounded received bytes in storage. Retry transient failures at most three times, retire permanent failures, retain useful quota-failed bytes within the spool budget, and clean up with session deletion.
• On startup, archive already-received bytes before sealing interrupted runs. Recover missing ACP publication references with exact run ownership and idempotent, explicitly marked hidden-to-model recovery messages; rediscover committed Markdown whose reception registration was interrupted. Sealed runs remain sealed.
• Start reception independently of viewport rendering. Admit originals up to 8 MiB while keeping previews at 2 MiB; saved larger originals expose an open-original action instead of appearing unsaved. Message reception status handles repeated references correctly.
• Advance Artifact SQLite schema 4→5 and Host compatibility epoch 229→230. Existing storage owns the migration. Document budgets, recovery and failure boundaries in docs/architecture/session-media-preview.zh-CN.md.

SVG parsing, SVG/XML code previews and preview caches remain in independent #6292. This PR uses raster rendering.

Verification

Tested head: 7a3265cd7669a333cc93baf7077fd9613bac9c57; build/test baseline: 222a06fe316f12df3129eff1c16ab3bfaf85c479.

• Independent branch: 214 focused tests and 24 Chromium image tests passed; full workspace typecheck, lint, changed-file format and ASF headers passed; desktop rebuilt.
• Combined with feat(ui): add bounded static SVG image and code previews #6292: full workspace build, typecheck, lint, headers, format, renderer architecture (168 checks) and surface inventory passed. All 417 tests in changed test files and 35 Chromium image/SVG tests passed. The 276-test focused subset also passed; these counts overlap.
• Coverage includes process death after receiving bytes, missing sources, publication crash gaps, retry persistence, spool pressure, session-deletion races, exact 8 MiB base64 admission, saved oversized originals and duplicate mounted references.
• Real Antigravity ACP 1.1.1 with the existing Google login and Gemini 3.8 Flash High generated a native 437,559-byte JPEG plus a body PNG. The live run confirmed byte-exact archives and reference-only tool publication. Final independent and combined binaries replayed those same real outputs, then hid the native source, removed the task-owned body source, fully restarted Electron, and verified rendering and original SHA-256 values. Eight assertions passed for each replay. No new generation was requested during final replay.
• The live native result contained one image part. Mixed text/image/diff/text, cancellation, transport loss and crash injection remain deterministic coverage. Generic conversation-copy reference rewriting is tested; provider-owned ACP conversation cloning remains unsupported. Packaged Windows/Linux checks were not run.

Governance acceptance report · Assertion records, merge simulations and checksums. Earlier before/after and performance evidence remains in the acceptance release.

Persistence boundaries

A source that disappears before bytes are received cannot be recovered. Invalid content, denied access, full disk and archive quota failures remain explicit failures. The 512-job / 32 MiB receive spool is bounded and may reclaim old quota-failed payloads while retaining their failure metadata. Recovery does not reopen sealed runs or publish late cancelled-run output. A canonical record beyond the recovery scan bound is skipped with a warning. These limits are covered in the architecture document rather than hidden by success wording.

Merge independence

Both PRs target main and can land in either order. They share a behavior-preserving image presentation/admission foundation; neither requires the other feature. Normal Git merges produce identical trees in both orders. This repository permits squash merges only: after either lands, sync the other with main and reconcile packages/core/src/image-delivery.ts, packages/ui/src/attachment-image.tsx, and packages/ui/src/session-media-image.tsx. Both squash orders were simulated against main a4b5f86c5256044d063a62045754e4a3411a8426; the reconciled trees are identical and retain the tested combined implementation. There is no prescribed merge order.

AI use

• No generative tool made a substantive contribution
• Generative tooling made a substantive contribution

Tool(s) and scope: Codex implemented the split and reception governance, added regression tests, performed real-account Electron acceptance, and updated documentation. Retain Generated-by: Codex in the squash commit.

Checklist

• Tests cover the change and fail without it
• Lint, format, typecheck and the affected suites pass locally

Does this PR entail a change in behavior?

• Yes — described under Summary above
• No