fix(reconciler): add from-state guard to transition_bead action handler

[jrf0110]

Summary

Adds a from-state guard to the transition_bead action handler in actions.ts. When action.from is non-null, the handler now fetches the bead via beadOps.getBead() and skips the transition with a warning log if the current status doesn't match action.from. When from is null, the transition applies unconditionally, preserving backward compatibility. This prevents stale transitions from concurrent rule firings in the reconciler (e.g., two rules both trying to transition a bead that has already moved to a different state).

Verification

• Typecheck passes
• Existing tests pass (2 pre-existing client.test.ts JWT failures are unrelated)
• Code review: single-file change, uses existing beadOps.getBead() import, consistent with codebase patterns

Visual Changes

N/A

Reviewer Notes

• The TransitionBead schema already defines from: z.string().nullable() — this change adds the runtime guard that was previously missing.
• The guard uses != null (not !== null) to also catch undefined, which is defensive.
• When the bead is not found, the guard logs a warning and returns null (no-op) rather than throwing, consistent with the existing try/catch pattern in the handler.

[kilo-code-bot]

Code Review Summary

Status: No Issues Found | Recommendation: Merge

Files Reviewed (1 files)

• cloudflare-gastown/src/dos/town/actions.ts

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_{Reviewed by gpt-5.4-20260305 · 274,913 tokens}