feat(plugin): a reply's sections are chosen, not filled (#4153)

Milestone 409 step 6 measured the scaffold on live sessions and found its
two halves disagreeing: adherence passed and the read test failed.
Completion replies carried every section the table asks for and were
still hard to read.

The cause was in the skill, not in compliance with it. It said to pick a
kind of reply "then fill its sections... keep them even when one is
short", which is an instruction to complete a form, and nothing anywhere
set a ceiling. A faithful reply and an unreadable one were the same
reply.

Four changes to the discipline around the scaffold. The categories and
their sections are untouched.

- Sections are what to consider including, not a form to complete. A
  section answering a standing question ("does anything need me?") is
  always answered, even with "nothing"; a section that explains earns its
  place only when it changes what the operator does. Otherwise it belongs
  in the record's log, where it is available and not in the way.
- Write the shortest reply that carries the answer, with named exceptions
  so this cannot be read as "always be terse".
- "Needs you" takes BOTH tests: theirs to decide, AND work is waiting on
  it. A question answerable by reading something or taking an available
  measurement is work not yet done, not a request — settle it, say which
  way you went, and leave them free to overrule.
- A decision already made gets acted on. Re-arguing a settled question
  reads as contradicting yourself rather than as being careful, and costs
  the operator the decision twice.

"Before sending" gains a second pass for what can go, since the existing
check asks what is MISSING, which a bloated reply passes.

Guards in tests/test_reply_discipline.py, three topics registered for
ownership. Every guard was falsified against the pre-change text before
committing (rule 167): all five fail on it and pass on the fix, and the
sixth deliberately passes both since it guards the scaffold against
collateral damage. No absence checks — the skill legitimately discusses
filling in order to warn against it, so asserting "fill" is absent would
false-alarm on the corrected text (snippet #3352).

Instance-agnostic per rule 115: the added text carries no record ids, no
software-specific terms and no verbatim quotes.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01821k5B3Ysecp9fNYs92Kuy

plugin/.claude-plugin/plugin.json

@@ -1,7 +1,7 @@
 {
   "name": "scribe",
   "description": "Scribe for Claude Code: connects the scribe MCP server, adds the hooks that deliver live project state and relevant records at the right moment, ships the shared client-neutral Scribe skills (using-scribe, writing-plans, reporting-back, systematic-debugging, verification, brainstorming, reusing-code, shape-accounting), and syncs your saved Scribe Processes as skills (/scribe:sync).",
-  "version": "2026.09.18.0436",
+  "version": "2026.09.18.1551",
   "author": {
     "name": "Bryan Van Deusen"
   },