Declared plan documents go stale after the agent edits them #1491

Problem

After an agent edits a plan, spec or design document it declared with declare_plan_document, the desktop app's Artefacts tab keeps showing the original text.

The server holds only the snapshot the CLI sent at declaration time. Nothing re-declares the document after an edit, and neither the tool description nor the SessionStart plans nudge asks the agent to.

The server also ignores a re-declared snapshot whenever its transcript reconstruction already has a complete revision; that half is fixed in kcap-server.

Fix (CLI)

• Record each accepted declaration locally, per session, with every argument.
• Add an async Claude PostToolUse hook on Write|Edit|MultiEdit that declares a recorded document again with its current text.
• Tell the agent, in the tool description and the plans nudge, to declare a document again after changing it (covers other harnesses and edits the hook cannot see).