docs(devpath): merge-driver comments say system-context.mdx has a generated register again, and why neither census page is routed

.gitattributes

@@ -95,17 +95,25 @@
 # the three hottest artifacts; each gate sums its shards when it reads them.
 #
 # The elevation census page (`content/docs/permissions/system-context.mdx`) was
-# routed here from #13646 to #22927 and is not any more: nothing on it is
-# generated. It joined as a `file:line` anchor table whose correct merged values
-# were on NEITHER side of a conflict, became a MIXED row when #14064 measured that
-# a whole-side deferral dropped its hand-written prose (`mixed: 'line-anchors'`),
-# lost its line numbers to `path#symbol` anchors at #15921, and lost its last
-# generated half — the census totals — to #22927's ruling. It text-merges like
-# its prose neighbours now. ⚠️ What still catches a merge that leaves it wrong is
-# `scripts/check-system-context-census.mjs`, which re-derives the census from the
-# tree on every PR in the required `Lint & Repo Gates` job: a read no row anchors,
-# or an anchor that no longer resolves. The `mixed` field and its comparator stay
-# for the next mixed artifact (scripts/regen-artifacts.mjs, scripts/git-merge-regen.mjs).
+# routed here from #13646 to #22927 and is not any more. It joined as a `file:line`
+# anchor table whose correct merged values were on NEITHER side of a conflict,
+# became a MIXED row when #14064 measured that a whole-side deferral dropped its
+# hand-written prose (`mixed: 'line-anchors'`), lost its line numbers to
+# `path#symbol` anchors at #15921, and lost its census totals to #22927's ruling,
+# which took this row and `gen:system-context-census` with them. #26442 gave it a
+# generated half again: the site register between its BEGIN/END GENERATED
+# markers, rebuilt by `node scripts/check-system-context-census.mjs --write`. It
+# stays unrouted, as `tenant-audit-census.mdx` beside it (a generated region that
+# `node scripts/tenant-audit-census.mjs --write` rebuilds) always has: both are
+# MIXED pages that git text-merges, so neither side's prose is dropped, and the
+# register carries one line per symbol and no total, so two read-adding branches
+# merge apart. ⚠️ What catches a merge that leaves a region wrong is that page's
+# gate, which holds the region equal to its `--write` output on every PR in the
+# required `Lint & Repo Gates` job (`scripts/check-system-context-census.mjs`,
+# `scripts/check-tenant-audit-census.mjs`). Why neither is routed is recorded in
+# NOT_DRIVER_MANAGED's `content/docs/permissions/**` entry; the `mixed` field and
+# its comparator stay for the next mixed artifact (scripts/regen-artifacts.mjs,
+# scripts/git-merge-regen.mjs).
 
 #
 # #13731 enumerated this file's blind spot and closed it: `check:merge-driver` now

scripts/git-merge-regen.mjs

@@ -174,9 +174,15 @@ const DECLARED_WATCH_HINTS = [
  */
 const MIXED_COMPARATORS = Object.freeze({
   /**
-   * Equal modulo `file:line` anchor numbers. The generated half of
-   * `content/docs/permissions/system-context.mdx` is exactly those numbers:
-   * `check-system-context-census.mjs --fix` rewrites them and touches nothing else.
+   * Equal modulo `file:line` anchor numbers. Written for
+   * `content/docs/permissions/system-context.mdx`, whose generated half was those
+   * numbers until #15921 made its anchors `path#symbol`; on that page it is now the
+   * identity (`scripts/doc-line-anchors.mjs` header), and the census `--fix` that
+   * re-anchored them is retired. No row names it today: the page left this driver
+   * at #22927, and the site register #26442 generated on it since lives between
+   * markers this comparator does not blank (`check-system-context-census.mjs
+   * --write` rebuilds it). Kept for the next `file:line` mixed artifact; a
+   * marker-region page would need a comparator of its own.
    */
   'line-anchors': blankAnchorLineNumbers,
 });
@@ -298,9 +304,10 @@ function readSide(file) {
  * Two shapes are lossless, and they are the ones the comparator can PROVE:
  *
  *   1. THEIRS differs from the ANCESTOR only in the generated half. Then theirs
- *      contributes nothing but numbers `--fix` will re-derive from the merged tree,
- *      and dropping it drops nothing. This is the common case by a wide margin —
- *      24 of the last 25 main commits to `system-context.mdx`.
+ *      contributes nothing but what the row's `gen:` re-derives from the merged
+ *      tree, and dropping it drops nothing. It was the common case by a wide margin
+ *      when `system-context.mdx` was the routed page this was written for — 24 of
+ *      its last 25 main commits, measured then.
  *   2. THEIRS and OURS agree once the generated half is blanked. Then whatever
  *      hand-written change theirs carries, ours carries too, so keeping ours keeps
  *      it. (Two branches landing the same doc edit, or one rebased onto the other.)

scripts/regen-artifacts.mjs

@@ -54,8 +54,9 @@ export const ROOT_OWNER = '@objectstack/spec-monorepo';
  * `mixed` is the third answer those two lists could not express. A file can be
  * mixed AND still belong here, when the generated half is unreachable by any text
  * merge (`content/docs/permissions/system-context.mdx` was the measured case, routed
- * from #13646 until #22927 retired the census totals that were its last generated
- * half; no row carries `mixed` today) — but
+ * from #13646 until #22927 retired its census totals; the site register #26442 has
+ * since generated on it is left to text-merge, for the reasons its
+ * `NOT_DRIVER_MANAGED` entry records; no row carries `mixed` today) — but
  * then "defer" is only correct for the merges where the discarded side changed
  * nothing but the generated half. The value NAMES that equivalence, and
  * `git-merge-regen.mjs` holds the mapping from the name to the comparator; an
@@ -237,10 +238,12 @@ export const REGEN_ARTIFACTS = Object.freeze([
   // row with `mixed: 'line-anchors'` (#14064 measured a whole-side deferral dropping
   // its prose). Its generated half was its `file:line` anchors until #15921 made
   // them `path#symbol`, then its census totals until #22927's ruling took those off
-  // the page with `gen:system-context-census`. Nothing on it is generated, so it is
-  // no artifact and has no row; it text-merges like the prose around it, and
-  // `check:system-context-census` still re-derives the census on every PR. The
-  // measurements this row carried are in `git log -p scripts/regen-artifacts.mjs`.
+  // the page with `gen:system-context-census`. #26442 then generated its site
+  // register (`check-system-context-census.mjs --write`), so it is MIXED again and
+  // still has no row: its `NOT_DRIVER_MANAGED` entry (`content/docs/permissions/**`)
+  // records why, and `check:system-context-census` holds the register to the tree
+  // on every PR. The measurements this row carried are in
+  // `git log -p scripts/regen-artifacts.mjs`.
 
   // #13335 / #13731. The per-skill reference index — one row per `packages/spec`
   // source module, rendered whole by `gen:skill-refs`. Nine tracked files today,
@@ -418,12 +421,24 @@ export const NOT_DRIVER_MANAGED = Object.freeze([
     path: 'content/docs/permissions/**',
     why:
       'the DIRECTORY is not what #13646 routed, and recording that is the point of this ledger. '
-      + 'Its pages are hand-written permissions prose. One — `system-context.mdx` — was routed as a '
-      + 'MIXED file from #13646 until #22927 retired the census totals that were its last generated '
-      + 'half; it is plain prose now and is routed nowhere. Routing the tree the way its sibling '
+      + 'Its pages are hand-written permissions prose, and two of them are MIXED: hand-written prose '
+      + 'around one generated region between BEGIN/END GENERATED markers. `system-context.mdx` was '
+      + 'routed as a MIXED file from #13646 until #22927 retired its census totals, and has carried a '
+      + 'generated site register since #26442 (`node scripts/check-system-context-census.mjs '
+      + '--write`); `tenant-audit-census.mdx` carries the census region `node '
+      + 'scripts/tenant-audit-census.mjs --write` rebuilds. NEITHER is routed, re-weighed at #26535: '
+      + 'a whole-side deferral would drop the other side\'s prose; the `mixed` escape would buy nothing, '
+      + 'since its one comparator, `line-anchors`, blanks `file:line` digits and is the identity on '
+      + 'both pages (measured), so every real edit would still take the driver\'s text-merge limb; a '
+      + 'row needs a `gen:` script its owner manifest declares, and neither page has one; and the '
+      + 'driver runs only in a local merge, never in GitHub\'s server-side one or the queue\'s. What '
+      + 'keeps them right is their gates, which hold each region equal to its `--write` output on '
+      + 'every PR and queue build in the required `Lint & Repo Gates` job, so a text merge that '
+      + 'leaves a region wrong is red, never silent; and the register carries one line per symbol and '
+      + 'no total, so two read-adding branches text-merge apart. Routing the tree the way its sibling '
       + '`content/docs/references/**` is routed reads as symmetry and is not: that sibling is '
       + 'generated whole, this one would defer every prose page to OURS and lose the other side\'s '
-      + 'edits silently. Should a generated page arrive here, route that FILE and leave its '
+      + 'edits silently. Should a page generated WHOLE arrive here, route that FILE and leave its '
       + 'neighbours to text-merge, which is correct for prose and always was.',
   },
   // ── #13731: the remaining generators, one recorded disposition each ──────────