🤖 feat: add a resolver for workspace model, thinking and reasoning picks

[ibetitsmike]

Summary

Adds the renderer resolver that the next layers switch to: getWorkspaceAiSelection (plain reader) and useWorkspaceAiSelection (hook) in workspaceAiSettingsSync.ts. For a workspace and agent it resolves each field from, in order, the unsent pick, the workspace's saved settings for that agent (aiSettingsByAgent, falling back to aiSettings), the agent's configured defaults, then the project default and the global default. A saved per-agent entry owns the reasoning mode, so an entry without one means standard. Creation composers (the reserved global, project, pending and draft scope IDs, isNonWorkspaceScopeId) keep resolving from their own project, global or draft defaults, in both readers; a legacy workspace whose ID starts with __ resolves as a workspace.

The pick store in aiSelectionIntent.ts gains what the resolver needs: a per-workspace copy of the AI metadata (setWorkspaceAiMetadata, fed by metadata loads in the desktop app and the VS Code webview), a reader for one pending pick, change notifications for the hook, and dropPendingModelPicks for provider removal. Nothing reads the resolver yet, so no behavior changes.

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 2 of 20.

Testing

• "each field falls through the unsent pick, saved settings, agent and project defaults" (workspaceAiSettingsSync.test.ts): each tier, including an unsent reasoning pick, wins over the ones below it for model, thinking level and reasoning mode.
• "the hook follows a default model that loads after it rendered" (same file): the hook picks up a global default that arrives after its first render.
• "a creation scope resolves its own defaults in the hook and the plain reader" (same file): a creation scope reads its scoped defaults, not the agent's configured model. It fails when either the hook's or the plain reader's creation-scope branch is removed.
• "a legacy workspace id that starts with __ resolves its saved settings" (same file): a legacy __<project>-<branch> workspace reads its saved settings, not creation defaults.
• The metadata seeding test in WorkspaceContext.test.tsx also checks that a non-archived metadata event reaches the resolver's store.
• 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 on a97db95b3f: 2 findings: 1 fixed in 86e280c, 1 declined with the reason in its thread. 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: two gaps here: the unsent reasoning pick tier and a default model that loads after render. Both tests above now fail when that code is removed.

[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 2026-10-09T00:27:57.558956Z	86e280c	New commits
🔒 Security Review	✅ Completed 2026-10-09T00:26:32.644110Z	86e280c	New commits

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Reviewed commit: a97db95b3f

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Reviewed commit: 86e280c72b

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[ibetitsmike]

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