fix(kiloclaw): attach status 404 to 'Instance not provisioned' errors

[jeanduplessis]

Summary

Problem

The start, stop, and destroy methods on KiloClawInstance threw plain Error objects when called on instances that were never provisioned. API route handlers that inspect error.status to determine HTTP response codes could not distinguish "not found" from internal errors, resulting in 500 responses instead of 404.

Solution

• Attach { status: 404 } to all three "Instance not provisioned" error throws via Object.assign in start(), stop(), and destroy().
• Add test coverage for each method confirming the error carries status: 404.

Why this approach

Object.assign on the thrown Error is the lightest change that gives callers a machine-readable status without introducing a custom error class. A custom HttpError subclass was considered but would be overkill for a single status code used in three places.

Verification

• pnpm typecheck — passed (all packages)
• pnpm test --run (kiloclaw) — 951 tests passed, 0 failed
• pnpm format — no remaining formatting issues
• pnpm lint — passed (pre-push hook)

Visual Changes

N/A

Reviewer Notes

• The three throw sites are in kiloclaw/src/durable-objects/kiloclaw-instance/index.ts at the entry guards of start() (line 693), stop() (line 947), and destroy() (line 994).
• Callers that already catch these errors and check .status will now get 404 instead of undefined. Callers that don't inspect .status are unaffected.

[kilo-code-bot]

Code Review Summary

Status: No Issues Found | Recommendation: Merge

Files Reviewed (1 files)

• kiloclaw/src/durable-objects/kiloclaw-instance/index.ts

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_{Reviewed by gpt-5.4-20260305 · 224,501 tokens}