fix(client): surface desktop AI stream request failures

[HandSonic]

Related issue

N/A - no matching issue was found.

Summary

Desktop AI SSE startup failures were rejected by the controller bridge without being delivered to the request-specific stream listener, leaving the consumer waiting indefinitely. Synchronous bridge callbacks could also fire before listener registration, while ordinary acknowledgement payloads could be mistaken for failures. This change normalizes controller/native failures into stream error events, defers synchronous dispatch until listener registration, settles missing or throwing bridges, and preserves normal acknowledgements.

The final manifest amendment keeps the expanded test:sse-request command but removes its redundant insertion into the shared prebuild chain. Community CI already invokes that named test directly, and the amendment avoids a merge conflict with the database-selector PR.

Affected surfaces

• Frontend / Web
• Backend / API / Storage
• Database plugin / Driver
• JCEF / Desktop packaging
• CI / Build / Release
• Documentation only

Verification

• Commands and results:
  • yarn test:sse-request: passed ownership, transport, and production adapter contracts.
  • Targeted ESLint for the desktop SSE adapter, failure helper, and tests: passed.
  • Full Community Umi/Webpack build, including the complete prebuild contract set: succeeded.
  • Production bundle verifier passed both as postbuild and standalone.
  • git diff --check origin/main...HEAD: passed.
  • Merge-tree with selector head 2828cf80e: zero conflict markers; both selector and SSE test scripts are retained.
  • Temporary fork verification PR 优化: 配置支持自定义 #85 at head 7aa7ea315a32fefe2b8a6039abf5cb108ffe67a9: Frontend, Backend, JavaScript CodeQL, and Java CodeQL all passed.
• Manual verification: N/A - deterministic event-bus tests cover controller envelopes, native rejection, synchronous callbacks, missing/throwing bridges, acknowledgements, and listener ordering.
• UI evidence: N/A

Risk and compatibility

• Public API or stored data: No public API or persisted-state changes.
• Database or driver compatibility: N/A.
• Network, privacy, or security: No new data flow; existing failure messages are routed to the owning stream request.
• Community / Local / Pro boundary: Shared Community desktop SSE adapter.
• Backward compatibility: Successful stream setup and normal acknowledgements keep their existing behavior; previously silent terminal failures now reject through the stream error path.

Reviewer map

• Start here: service/sse/requestFailure.ts, then service/sse/index.tsx and the adapter tests.
• Failure condition: a controller/native setup failure leaves the stream pending, a synchronous callback is lost before listener registration, a normal acknowledgement is emitted as an error, or the manifest conflicts with selector head 2828cf80e.
• Rollback or disable path: Revert commit 7aa7ea315a32fefe2b8a6039abf5cb108ffe67a9; no migration is required.

Contributor declaration

• I linked the Issue that defines this change.
• I tested the affected behavior and reported the actual results above.
• I did not include credentials, private data, or generated build output.
• I disclosed substantial AI assistance below, or this PR contains no substantial AI-generated code.

AI assistance: OpenAI Codex assisted with diagnosis, implementation, automated tests, verification, conflict analysis, and adversarial review.

Latest-main revalidation (2026-09-04)

• Rebased onto upstream 144a04e; current head 7aa7ea3.
• SSE ownership, transport, and desktop request-failure tests passed; targeted ESLint passed.
• Included in the green combined Community production build and bundle verification.