[Fix] kimi-code provider: register approval handler so hosted sessions can exit plan mode

[L42y]

Symptom

A hosted kimi-code agent session deadlocked in plan mode: the agent called ExitPlanMode 9 times and every call was dismissed with the synthetic result "Plan approval dismissed. Plan mode remains active." Plan mode then kept denying all writes (CronCreate, Edit, and every other write tool), so the hosted agent could make no progress at all.

Root cause

• The First Tree kimi-code provider (packages/client/src/providers/kimi-code/index.ts) runs headless sessions with permission: "yolo" and never registers an approval handler.
• Inside @botiverse/kimi-code-sdk, ExitPlanModeReviewAskPermissionPolicy escalates ExitPlanMode to an approval request in every permission mode except "auto" — including "yolo".
• The headless RPC requestApproval returns {decision: "cancelled", feedback: "No approval handler registered."} when no handler is registered.
• Result: plan exits are auto-cancelled forever, plan mode stays active, and plan mode keeps blocking writes — a permanent deadlock with no interactive surface to recover through.

Fix

Register a module-level approval handler on every kimi-code session, on both the create and resume paths:

• If the request is a plan exit (toolName === "ExitPlanMode" or display.kind === "plan_review"), return { decision: "approved" } — restoring the intended yolo posture for hosted sessions.
• Otherwise return { decision: "cancelled", feedback: "No interactive approval surface in hosted sessions." } — matching the previous handler-less behavior for everything else.

First Tree code only; the SDK and patches/ are untouched.

Test coverage

packages/client/src/providers/kimi-code/__tests__/handler.test.ts:

• FakeSession gains a setApprovalHandler spy.
• New test: after start and resume, the handler is registered; invoking it with an ExitPlanMode/plan_review request returns { decision: "approved" }; invoking it with a non-plan request (Bash) returns cancelled with the hosted-session feedback.

Verification

• pnpm --filter @first-tree/client exec vitest run src/providers/kimi-code/__tests__/handler.test.ts — all tests pass (including the new one).
• pnpm --filter @first-tree/client typecheck — clean.
• biome check on the two touched files — clean.

[baixiaohang]

Recommendation: approve

• Rationale: The change closes the hosted Kimi plan-mode deadlock at the provider boundary while preserving fail-closed behavior for every non-plan approval request.

Risk level: A

• Path baseline: includes packages/client/** -> A
• Semantic lift: none

PR summary

• Author / repo: L42y / first-tree-ai/first-tree
• Problem: A hosted Kimi agent that enters plan mode cannot obtain interactive approval, so every exit attempt is cancelled and all subsequent writes remain blocked.
• Approach: Register one hosted-session approval handler before the first prompt on both create and resume. It approves plan-exit requests and cancels all other requests with explicit hosted-session feedback.
• Impacted modules: packages/client/src/providers/kimi-code/

Review findings
✅ 1. The pinned SDK confirms that valid ExitPlanMode calls require approval outside auto mode and that a missing handler returns cancelled; the fix addresses that exact boundary.
✅ 2. Registration covers both session creation and restoration before provider input, and the SDK clears the handler when the session closes.
✅ 3. Non-plan approvals remain fail closed, so the change does not broaden the hosted runtime's general approval surface.

Action taken

• Approved the unchanged head f213bc5e8ed0485a6d2edf7ae5cd29f4888fc489 after explicit maintainer authorization.

[yuezengwu]

Reviewed exact head f213bc5e8ed0485a6d2edf7ae5cd29f4888fc489.

The provider registers the hosted approval handler before the first prompt on both create and resume. The pinned SDK evidence confirms that non-auto plan exits are otherwise routed through approval and that missing handlers return cancelled; SDK session close also clears the handler. Non-plan approval requests remain fail closed.

Independent validation in a clean detached worktree:

• pnpm --filter @first-tree/client exec vitest run src/providers/kimi-code/__tests__/handler.test.ts — 38 passed
• pnpm --filter @first-tree/client typecheck — passed
• pnpm exec biome check packages/client/src/providers/kimi-code/index.ts packages/client/src/providers/kimi-code/__tests__/handler.test.ts — passed
• git diff --check — passed