docs(corpus): advance the corpus submodule to the corpus that carries the armed ! marker rule (#209)

src/content/docs/recipes/internals/cutover-policy.md

@@ -138,6 +138,8 @@ One PR, one commit, with these deliverables:
 
 The commit uses the Conventional Commits `!` breaking-change marker; the body lists every deleted identifier, every removed YAML field, and every updated test. `charly migrate` is runnable against old projects from that commit forward, with no additional steps.
 
+**The marker is the subject's half of the cutover's question — "does this change break a consumer?" — and the body's `## Change classification` answers the other half: what breaks for THIS repo's consumers, and how to roll it back.** So a marker-carrying subject MUST come with a `**Breaking change + rollback:**` line, and a bare `none` is not an answer: a cutover that breaks nothing here must say WHY it breaks nothing here (for example: *"none — the pointers move to commits the org has already merged"*). *Detail:* [`/charly-internals:git-workflow`](/recipes/internals/git-workflow/) ("The `!` marker and the body's breaking-change answer").
+
 See `CHANGELOG/` for the catalog of past cutovers that followed this shape — each took the same steps: **delete old surface + publish migration + hard load error**.
 
 ## When the policy might not apply

src/content/docs/recipes/internals/git-workflow.md

@@ -149,6 +149,18 @@ blocks PRs: in one leg, five verdicts on one PR turned on prose while the code a
 here, the two cannot both be the disposition.* **Grep the body for every statement about a responsibility and reconcile
 them before the push — being scrupulous is not the same as being consistent.**
 
+### The `!` marker and the body's breaking-change answer
+
+**The subject's `!` and the body's "Breaking change + rollback" line answer ONE question, and the body must answer it whenever the subject carries the marker.** The subject's Conventional Commits `!` says the change is part of a **HARD CUTOVER** — the whole phase lands in one change, with no shim, no dual path and no follow-up ([`/charly-internals:cutover-policy`](/recipes/internals/cutover-policy/)). The body's `## Change classification` says **what breaks for THIS repo's consumers, and how to roll it back**. The body's side is therefore:
+
+- **Under a `!`, `## Change classification` MUST carry a `**Breaking change + rollback:**` line.** It names the breakage this repo's consumers see, and the way back.
+- **A bare `none` is NOT an answer.** A cutover that breaks nothing HERE must say WHY it breaks nothing here — *"none — the pointers move to commits the org has already merged"* is an answer; *"none"* alone is not.
+- **Without a `!`, the line is optional.** A body that declares a breakage without the marker is judged on its own merits, and the marker is never inferred from the line.
+
+**Why the section's CONTENT is required, not only its NAME.** The body's sections are checked for FORM — the four required headings, the trailer's position, the head SHA, the file table — so a body can carry a perfectly well-formed `## Change classification` that says nothing about the change. Under a `!` that is the one thing the merged changelog must not do: the record would carry a cutover marker and a silent answer side by side. Measured org-wide: of the **53 bang-marked merged pull requests** in the scanned window, **51 carry no breaking-change answer at all**; the two that do (opencharly/opencharly#801 and opencharly/plugin-box#66) both answer with a REASONED `none`, and **not one of the 53 carries a bare `none`** — so the silence is the measured defect, and the bare-`none` rule is the one that must hold BEFORE the org writes such a body. The gap the silence left is opencharly/opencharly#802.
+
+**The umbrella's own reconciler checks the relation mechanically.** `scripts/check-pr-body-diff.mjs` reads the head's subject (`git log -1 --format=%s <head>`) and the body's `## Change classification`, and blocks a bang-marked head whose body carries no answer, or a bare `none`. It runs in the pre-push gate (`hooks/pre-push`), so the relation is settled BEFORE the push rather than by a reviewer afterwards. Its self-test carries all three directions: the bang-marked head with no answer and the bang-marked head with a bare `none` go RED, and the bang-marked head with a reasoned `none` stays GREEN.
+
 ### The POISON state — green verdict, still BLOCKED
 
 A branch protection rule requires ALL same-name `validate / validate` check runs on