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/skills/reporting-back/SKILL.md

@@ -0,0 +1,122 @@
+---
+name: reporting-back
+description: Use when you are about to write the reply the operator will read — work finished, a task marked done, stopping on a blocker, asking them to decide or to do something, answering "where are we" / "what's next", or proposing an approach. Shapes the reply around where the work stands (which task, what changed, what needs them, what comes next) instead of the order you did things in. Triggers on reporting completion, handing off, asking a question, or summarising progress.
+---
+
+# Reporting back
+
+Your reply is where the operator finds out what happened. They were not there
+while you worked: they don't hold the files you read, the names you used or
+the order you did things in. A reply that follows *your* path is accurate and
+still unreadable to them. Shape it around **where the work stands**.
+
+Pick the kind of reply first (the tables below), then fill its sections. The
+sections are what lets the operator find things at a glance, so keep them even
+when one is short — "**Needs you:** nothing" is an answer they were looking for.
+
+## Every reply
+
+- **Conclusion first.** The verdict, the result, or the question — before the
+  reasoning that supports it.
+- **One topic per section.** Two things the operator raised get two sections.
+- **Make priority visible.** Bold the few things that matter; let the rest be
+  plain.
+- **End with the ask, in bold** — the one thing they need to decide or do. If
+  there is nothing, say so.
+- **Plain words.** Use the operator's vocabulary, not the names you coined while
+  working. If a term has to appear, explain it once.
+- **Place the work in Scribe.** Name the task, issue or milestone it belongs to,
+  by id *and* title (using-scribe: "Name the record, never just its number").
+
+## Take the placement from the record
+
+A remembered milestone title or "next step" reads exactly like a real one when
+it is wrong. So take placement from Scribe:
+
+- `update_task` and `create_task` return a **`placement`** block — the project,
+  the milestone, `position` (step N of M), `progress`, and `next` (the next open
+  step). Use those values as they came back.
+- For a wider view, `get_milestone` (a plan and its steps) or `enter_project`
+  (the whole project).
+- Work with no task behind it: say so plainly — "this wasn't tracked as a
+  task" — and offer to record it. An honest "untracked" is a placement too.
+
+## Reports — work happened
+
+| Kind | Sections |
+|---|---|
+| **Completion** | Where this sits · What now works · How / why · Needs you · Next |
+| **Finding** (a problem you found and did not fix) | Symptom · Cause · Size of the fix · **Offer to fix it** |
+| **Blocked / failed** | What stopped · What you tried · What you need from them |
+| **Progress** (mid-work) | One or two lines: where things are, what's next, any blocker |
+| **Where are we** | The milestone and its progress · Done · Open · Needs you · Next |
+
+## Asks — the operator needs to act or decide
+
+| Kind | Sections |
+|---|---|
+| **Decision** | The question first · 2–4 options, each with what it changes · recommendation first |
+| **Clarification** | "My reading is X · the gap is Y · unless you say otherwise I'll do Z" |
+| **Handoff** (only they can do it) | The action · why it needs them · what it unblocks · what you'll do after · any way to skip it |
+| **Conflict** (what you're about to do clashes with a rule, a plan or an earlier decision) | What it says · what you were about to do · where they clash · A or B? |
+
+Before asking, check whether you can find the answer yourself — something that
+can be read or looked up is a fact to check, not a question to send.
+
+## Answers — the operator asked something
+
+| Kind | Sections |
+|---|---|
+| **Explanation** | The answer first · then the evidence, pointing at what they could open to check it |
+| **Evaluation** ("can we / should we") | Verdict · What exists · The gaps · Recommendation |
+
+## Proposals — shaping future work
+
+| Kind | Sections |
+|---|---|
+| **Options** | 2–3 approaches · the trade-off of each · one recommendation |
+| **Plan** | Goal · Steps · Open questions — for review before starting (writing-plans) |
+| **Review** | Findings ranked by how much they matter, one per item |
+
+## The completion report, in full
+
+The most common reply, and the one most often written in the order the work
+happened. The shape:
+
+> **Where this sits:** milestone 12 "Move the backups offsite", step 3 of 5.
+> Task #340 "Schedule the nightly sync" is done.
+>
+> **What now works**
+> - The nightly sync runs at 02:00 and copies the photo library to the remote
+>   store.
+>
+> **How / why**
+> - Used the scheduler the other jobs already use, so there is one place to
+>   look when a job doesn't run.
+> - Verified by running it once by hand and checking the remote copy's size
+>   matches the source.
+>
+> **Needs you:** nothing.
+>
+> **Next:** #341 "Alert when a sync fails". Starting it unless you redirect.
+
+Notes on each section:
+
+- **Where this sits** — from `placement`. If the work isn't under a milestone,
+  the task alone is enough.
+- **What now works** — outcomes the operator would notice: "You can now…",
+  "X no longer…". The files and steps behind them belong in the task's log.
+- **How / why** — only the decisions worth knowing, plus **how it was
+  verified**. If something could not be verified, say what and why here rather
+  than letting it read as passed.
+- **Needs you** — an action, an approval, a decision, or "nothing". If it's an
+  action, give the reason with it.
+- **Next** — from `placement.next`, or say the milestone is finished. If you
+  found something you didn't fix, the offer to fix it goes here.
+
+## Before sending
+
+Read the reply as the operator will: someone who wasn't there, reading
+quickly. Can they tell **what was done, whether anything needs them, and what
+happens next** without asking a follow-up? If not, the sections are what's
+missing — not more detail.