🤖 tests: check workspace model changes through the change record and AI selection

[ibetitsmike]

Summary

The agent-switch sync test and three UI model tests read the per-workspace model:{workspace} key, which stops being the source of the model in #5901. They now check what holds before and after that switch: the explicit model change record in the WorkspaceModeAISync test, and getWorkspaceAiSelection, which unsent picks and backend metadata already feed, in the UI tests. Production code does not change.

Stack

Milestone M4 of the server-side settings stack, on top of M3 (#5869 to #5879): per-workspace AI picks (model, thinking level, reasoning mode, agent and Auto routing) are stored in workspace metadata in config.json instead of per-browser localStorage keys, so every browser shows the same picks. An unsent picker change stays in memory in its tab until a send saves it, and a reload before sending drops it, as the plan accepts. Layer 6 of 20.

Testing

• "only records explicit model changes when agentId changes" (WorkspaceModeAISync.test.tsx) checks the change record without seeding or waiting on the model key.
• "only a sent deliberate pick pins; plain sends and backend reseeds never do" (reawakenAiPins.test.ts), and the model selection steps in thinkingPersistence.test.ts and thinkingSelector.test.ts, read the model through getWorkspaceAiSelection.
• The rewritten checks pass on the code before the switch in 🤖 refactor: resolve the workspace model from metadata and an unsent pick #5901 and after it, and the old key forms fail after the switch (verified for WorkspaceModeAISync and the jest suites reawakenAiPins, thinkingPersistence and thinkingSelector).
• make static-check and the touched test suites pass at the top of the stack; CI checks each layer on its own.

Review record

• Remote UAT through Coder Agents: Round 1: FAIL on efe7e29096, because a fork without a message dropped the source's unsent picks (fixed by 🤖 feat: fork a workspace with the source composer's unsent AI picks #5897, 🤖 refactor: resolve the workspace agent from metadata and an unsent pick #5908 and 🤖 refactor: resolve auto routing from the unsent pick, saved flags and agent defaults #5909); everything else passed. Round 2: PASS on 80f2b5379e: forks from all five entry points keep the unsent picks, startup removes the retired keys, and the round 1 checks still pass; the plan handoff was not exercised because the mock model cannot propose a plan. The Codex round 1 fixes made since then have no remote UAT yet; that is left to the next UAT round on 🤖 refactor: keep preferences and workspace AI picks on the server #5916.
• Codex round 1: thumbs-up on 009ac75b95, no findings. Mike asked to land the stack as one PR, so further review runs on 🤖 refactor: keep preferences and workspace AI picks on the server #5916.
• M4 test audit: no gap found in this layer (audit at efe7e29096, probe edits in production code).

[chatgpt-codex-connector]

Codex Review Summary

This comment shows the latest Codex review activity on this pull request.

Review	Status	Commit	Review trigger
📝 Code Review	✅ Completed 2026-10-09T00:25:23.048454Z	568a055	New commits
🔒 Security Review	✅ Completed 2026-10-09T00:25:48.750237Z	568a055	New commits

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[ibetitsmike]

Landed in #5916 (7b9899d), which collapsed this stack into one squash merge.