feat(409): the reporting reflex reaches every surface a session reads (#4012)

Step 3 of milestone 409 "Response shapes". Step 2's reporting-back skill
only helps if it fires, and only exists in the Claude Code plugin.

- scribe_static_context.md and using-scribe (new reflex 11) say: report back
  in a shape the operator can read, placed from the `placement` block rather
  than memory, and point at the reporting-back skill. using-scribe also lists
  it among the sibling process-skills.
- update_task returns a one-line `report_back` cue when a task is closed
  (done or cancelled). A tool response is the only surface every MCP client
  sees, at the moment the report is about to be written.
- _INSTRUCTIONS takes no line: there is no budget without trading out a
  session-start reflex. The decision is recorded in server.py's comment
  block so it is not re-litigated blind.
- Guards: test_instruction_surfaces_agree pins the reflex and the placement
  pointer on both plugin surfaces; a tool test pins the cue on closing
  statuses and its absence on every other update.

Plugin version minted.

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

plugin/hooks/scribe_static_context.md

@@ -55,6 +55,12 @@ for the operator's work, and as your own working memory across sessions.
   moment it's complete. When you **fix** something — even in passing — record it
   as its own issue (`create_task(kind="issue")`), not as a work-log line on an
   unrelated open task.
+- **Report back in a shape the operator can read** — they were not there while
+  you worked, so organise each reply around where the work stands rather than
+  the order you did things in: which task or milestone it belongs to, what now
+  works, what needs them, what comes next. Take the placement from the
+  `placement` block task writes return, not from memory. The `reporting-back`
+  skill holds the shape for each kind of reply.
 - **Tag to Systems as you write** — `enter_project` lists the project's
   Systems (its named subsystems/areas). When you create or meaningfully update
   a record, ask which areas it is about and pass `system_ids`; if an area has