fix(coding-agent): preserve live extension context when attaching handler abort signals

[Yeachan-Heo]

Signed status

CONFIRMED / ACTIONABLE / OWNER: @Yeachan-Heo

Dev CI run https://github.com/Yeachan-Heo/gajae-code/actions/runs/30890523179 failed on exact merged dev commit ded5926ad3c538a680449d61c1d31ac508499b2e in test:@gajae-code/coding-agent:shard-3-of-8.

Exact failures

• sdk-default-model-selection-e2e.test.ts: model.set executes every Q10-advertised selection and persists the public current readback retained initial-model instead of the selected reasoning-model.
• sdk-host-wiring.test.ts: lifecycle teardown swallows dual owner failures... rejected instead of resolving.
• sdk-host-wiring.test.ts: session_start swallows startup plus owner-release failure... rejected instead of resolving.
• Evidence producer and final affected-path validation then failed closed as cascades.

Attribution

PR #3814 only changed TUI scheduler/test/changelog files. It triggered the coding-agent dependent shard and exposed, but did not cause, the failure.

All three failures reproduce at #3805 merge commit 0aa86a4c9537b2327145e09661de0aa85c95c16f and all pass at its parent 9477947f8. The regression is introduced by #3805's { ...ctx, signal } handler-context copy in ExtensionRunner:

• spreading eagerly evaluates the live model getter, freezing the initial model for SDK model-control handlers;
• the spread occurs outside the runner's handler error boundary, so a context getter failure rejects runner.emit() instead of being contained.

Repair lane

Replace eager value spreading with a property-descriptor-preserving per-handler context carrying its own abort signal. Add focused coverage for live getters and error containment, then validate the three exact failures plus runner timeout behavior and targeted coding-agent checks.

No CI rerun/cancel, merge, canonical fast-forward, main, release, or #3805 evidence mutation is authorized.

Signed-off-by: Bellman gaebal-gajae@users.noreply.github.com

[Yeachan-Heo]

SIGNED STATUS — REPAIR OPEN

Sole repair lane: fix/issue-3817-live-extension-context

Owner PR: #3818 — #3818

Commit: b500f288e

Focused validation is green: 112 tests across the runner, exact SDK model-selection failure, and exact SDK lifecycle failure file; coding-agent Biome/TypeScript check is green. No merge or CI control action taken.

Signed-off-by: Bellman gaebal-gajae@users.noreply.github.com

[Yeachan-Heo]

SIGNED STATUS — VALIDATED / OPEN, NOT MERGED

PR #3818 CI is terminal green at head b500f288e5050b770a78574904b9ecca9efa634d:

• Dev CI run 30896166189: success.
• Affected path validation / test:packages/coding-agent/test/extensions-runner.test.ts: success.
• Affected path validation / check:@gajae-code/coding-agent: success.
• PR rollup: 15 success, 6 skipped, 0 failed/pending.
• Local exact-failure coverage: 112 pass / 0 fail across extensions-runner, sdk-default-model-selection-e2e, and sdk-host-wiring.

Coverage gap: the complete local shard cannot produce a clean operator-home receipt because unrelated file-lock GC discovery reaches its 20,000-entry cap; isolated HOME/config substitutions perturb unrelated plugin/LSP discovery fixtures. The three original run-30890523179 failures are directly reproduced red before the fix and green after it.

#3805 merge evidence remains unchanged. Canonical dev remains at 0aa86a4c9, one commit behind red origin/dev; no fast-forward occurred.

Signed-off-by: Bellman gaebal-gajae@users.noreply.github.com