Allow consecutive edits during slidedeck refinement

[ladislas]

Summary

Allow consecutive edits during slidedeck refinement. Priority: P2.

Motivation

The pending revision authorization is cleared after the first edit, although subsequent edit calls still require it. A focused handler-sequence reproduction allowed the first edit and blocked the second edit of the same newly copied revision.

Reviewed source: extensions/slidedeck/index.ts. Revalidate against current main before implementation.

Acceptance Criteria

• A permitted fresh revision can receive multiple consecutive edits during its refinement flow.
• Authorization remains scoped to the permitted revision; unrelated or original deck edits remain blocked.
• Completion, cancellation, failure, and restoration/reload have explicit state transitions without stale authorization.
• Lifecycle coverage exercises copy → edit → edit, an unrelated target, and state restoration rather than only individual helper outputs.

Scope and verification

Preserve the existing revision-copy policy. Fix the state lifetime rather than weakening edit checks.

Run affected regression coverage and required repository checks; update relevant documentation/changelog under repository conventions.

Type

AFK — independently implementable; push/merge authorization remains governed by the session and shared procedures.

Parent

#466

Blocked by

None — can start immediately.