fix(server): isolate V2 Cursor metadata and own request cleanup

[saphid]

Cursor metadata generation used write-capable agent mode in the project directory. Use an isolated temporary workspace, plan mode, sandboxing, and no ambient settings for title, branch, commit and PR text generation.

Keep the 180-second caller deadline through stalled workspace or SDK acquisition. Application-provided CursorRequestLifetime owns SDK completion and cleanup; provider-instance closure requests cancellation without destroying the workspace before SDK settlement. Application shutdown cancels remaining fibers and retains unsettled workspaces. No imperative Effect runtime bridge remains.

Current head 2b68f136d is based on V2 7dd9873ed with test-only prerequisite #10865 (merge first). Validation: 15 text-generation/driver/registry tests and server typecheck, targeted lint and formatting pass. New CI pending. No authenticated Cursor call was made. Direct Claude Opus 5 high review was retried for this change and exited 1 due to expired OAuth before inference; no independent review occurred.

Targets V2 #2829; #9914 is the separate ACP implementation for main. Updated with GPT-6 in Codex/T3.

[macroscopeapp]

Approvability

Verdict: Not approved

Macroscope's review found this PR not approvable — This PR changes the default execution model for every Cursor metadata-generation request and adds substantial asynchronous request, cancellation, sandbox, and temporary-workspace lifecycle behavior. It also introduces a static-analysis diagnostic suppression in tests, so the combined scope and policy impact warrant human review.

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[cursor]

Bugbot is paused — on-demand spend limit reached

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A team admin can raise the spend limit in the Cursor dashboard, or wait for the next billing cycle to continue.

[saphid]

Independent automated first-pass review (Amp/Astra): 1 finding. Addressed in f8a04ca: provider-scope close while a metadata request was in flight permanently leaked the temporary workspace (the interrupt exit branch only requested cancellation, and the scope-close test asserted the leak). The completion fiber now starts immediately so its exit finalizers always run, and workspace removal is scheduled once the SDK request settles. Verified with the 8 focused Cursor text-generation tests, server typecheck, and targeted lint.

[macroscopeapp]

Macroscope has since reviewed this pull request. An earlier review was skipped by a cost limit; a review has now completed, so that notice no longer applies.

[cursor]

Bugbot is paused — on-demand spend limit reached

Bugbot uses usage-based billing for this team and has hit its on-demand spend limit.

A team admin can raise the spend limit in the Cursor dashboard, or wait for the next billing cycle to continue.

[macroscopeapp]

Effect Service Conventions found three blocking convention violations. See the inline review comments for the expected fixes.

^{Posted via Macroscope — Effect Service Conventions}