fix(perf): retire idle provider resources

[astyfx]

Summary

Long-running provider sessions could retain completed Codex thread resources,
quiet streams could lose their replay window, and failed host children could
survive a transport error. This change gives provider resources explicit idle
lifetime boundaries and keeps the live chat clock local to the row that renders
it.

Changes

Fixes

• provider: unsubscribe idle Codex threads, retire idle App Server clients, and
  release turn ownership from one outer cleanup path
• streams: retain quiet active turns for replay and expire completed buffers
  through an independent timer
• host: escalate a failed child from SIGTERM to SIGKILL while retaining the
  original child reference
• chat: move elapsed-time updates from the conversation list into the live
  message row

Refactors / Chores

• add lifecycle and end-to-end regression coverage for provider, host, stream,
  and message-clock behavior
• document the resource ownership and recovery contracts

Test Evidence

• bun run test:isolated — 5,247 shared tests passed; 35 isolated suites passed
• bun run typecheck and bun run typecheck:lens-main passed
• bun run check:licenses, check:switch-exhaustiveness,
  check:max-lines-ratchet, check:doc-paths, and check:reliability-gates
  passed
• bun run build and bun run build:desktop passed
• focused lifecycle, stream, host, and Codex runtime tests passed

Notes

The raw bun test command runs process-wide module mocks together; the
repository's isolated test runner is the CI path and was used for the full
suite. Resource retirement is bounded and reversible: the next request starts
a fresh App Server and resumes the persisted thread when needed.

[upwind-code-us]

Upwind Code Scan - 🔍 Scan in progress…

Upwind is scanning this PR. Results will appear here when the scan completes.

[upwind-code-us]

Upwind IaC Scan - ✅ Passed

0 newly introduced misconfigurations · 0 resolved · 0 total in this PR vs main

View full analysis in Upwind Console →

Scan completed in 10s

Scan history (1 scan)

Commit	Scanned at	New	Resolved	Net
592cc31 <	2026-09-08 12:42 UTC	0	0	0

Last scanned: 592cc31 · 2026-09-08 12:42 UTC

[heath-s]

Approved