feat(409): the reporting-back skill shapes the reply the operator reads (#4011)

Step 2 of milestone 409 "Response shapes". A reply written in the order the
work happened is accurate and still unreadable to someone who was not there.
The new bundled skill shapes it around where the work stands.

- Fires when an agent is about to report completion, hand off, ask the
  operator something, answer "where are we", or propose an approach.
- Every reply: conclusion first, one topic per section, visible priority,
  the ask in bold at the end, plain words, the work placed in Scribe.
- Placement is taken from the placement block step 1 returns (#4010), not
  recalled; untracked work is said to be untracked.
- Four families of shapes: Reports, Asks, Answers, Proposals, with the
  completion report written out in full.
- Domain-neutral: the worked example is a backup job, evidence is "what you
  could open to check it". Written as practices, and naming no instance rule.
- A structural guard pins the completion sections, the from-the-record
  placement, and the absence of software-only vocabulary.

Listed in the plugin README and manifest description; version minted.

Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>

plugin/README.md

@@ -11,7 +11,8 @@ instance into a first-class Claude Code extension:
   file about to be written against your recorded snippets (what's kept at that
   path, and what resembles the code) and offers them before the helper is
   rewritten. Titles only, never blocks the edit.
-- **Universal process-skills** — using-scribe, writing-plans,
+- **Universal process-skills** — using-scribe, writing-plans, reporting-back
+  (reply to the operator in a shape that says where the work stands),
   systematic-debugging, verification, brainstorming, reusing-code (record and
   recall reusable code as snippets). Replaces superpowers.
 - **Your Scribe Processes as skills** — saved Processes are synced into local