Run the comment vocabulary check over the whole tree

The programme-vocabulary check only read src/, and its header recorded
everything outside src/ as an unexamined gap. Split the pattern
instead: the alternatives that have no legitimate use anywhere now run
over the whole tree (excluding this script, which matches itself), and
the two that are ordinary prose outside src/ stay src/-only. Those are
"in Step N", which the documentation uses for its own step
cross-references, and "this PR", which the contributor guides use for
the PR under review.

Add "architectural plan" and "follow-up wiring" to the tree-wide
alternatives and "this PR" to the src/ ones, matching the comments the
previous changes rewrote. The header now says the guard covers
committed documents as well as source comments, records why check 2
stays src/-only, which alternative is most likely to catch legitimate
prose later, and the gaps this guard does not close: phrasing too
common to deny, lowercase workspace paths, and bare commit hashes, with
the rule applied to hashes by hand. The script is now the only copy of
its patterns.

testing/check-comment-refs.sh

@@ -1,7 +1,7 @@
 #!/bin/bash
-# ── Source comment reference guard ──────────────────────────────────────────
-# Every reference a source comment makes must resolve for a reader who has
-# only this repository.
+# ── Comment and document reference guard ────────────────────────────────────
+# Every reference a source comment or committed document makes must resolve
+# for a reader who has only this repository.
 #
 # A comment that names a private planning artifact — by identifier, by file
 # path, or in programme vocabulary that has no in-repo referent — is dead text
@@ -22,17 +22,42 @@
 #      documents nobody has thought of. Scoped to src/ because resolving the
 #      whole tree's relative documentation links against the repository root
 #      is a different checker with its own population to triage first.
-#   3. programme vocabulary, scoped to src/. Phase, rung, milestone and step
-#      labels that name a plan a reader cannot open. The pattern is shared
-#      verbatim with the sweep that produced today's clean tree, so the two
-#      cannot drift apart.
+#   3. programme vocabulary, repo-wide in two scopes. Phase, rung,
+#      milestone and step labels, and phrases such as "architectural plan",
+#      that name a plan a reader cannot open. VOCAB_PAT runs over the whole
+#      tree except this file, which would match itself. SRC_VOCAB_PAT adds
+#      two alternatives that run over src/ only, because outside src/ they
+#      are legitimate prose: "in Step N" is the documentation's own step
+#      cross-referencing, and "this PR" is how CONTRIBUTING.md and
+#      PR-REVIEW.md talk about the PR under review. This file is the only
+#      copy of both patterns.
+#
+#      The tree-wide alternatives had no hit outside src/ when the scope was
+#      widened. The one most likely to catch legitimate prose later is
+#      \b[RQ][0-9]\b, which matches "Q4" or "R2" as words. If it does,
+#      rephrase the text or move that alternative to SRC_VOCAB_PAT; do not
+#      exclude the file or directory, which drops every other alternative
+#      with it.
 #
 # Known coverage gaps, recorded rather than discovered:
 #   - a bare "milestone" in some other phrasing (the narrow alternatives keep
 #     the Tor bootstrap loop in src/transport/tor/mod.rs out of check 3);
 #   - the CATEGORY_D / CATEGORY_E code identifiers and test names, which
 #     check 3's case-sensitive Category-[A-Z] deliberately does not match;
-#   - programme vocabulary, or a document path, outside src/;
+#   - a document path outside src/. Check 2 resolves a token against the
+#     repository root, but documentation links outside src/ are relative to
+#     the citing file, so widening it means a different resolver and a
+#     triage of the links that fail it;
+#   - a private-workspace directory cited in lowercase (an issues/... or
+#     tasks/... path with no .md token). Check 1's identifier prefix is
+#     case-sensitive and check 2 only resolves *.md tokens;
+#   - programme phrasing too common to deny, such as "a later step" or
+#     "the plan": an alternative for it would red legitimate text, so it
+#     passes check 3 by design;
+#   - bare commit hashes. Whether a hash resolves depends on the clone's
+#     object database, and GitHub CI clones are shallow, so a check would
+#     read differently on different hosts. The rule applied by hand is that
+#     a comment cites a commit only if a trunk branch contains it;
 #   - a reference to a private artifact made in free prose with no marker at
 #     all, at any scope: no check here matches it;
 #   - a pathspec typo introduced after this file lands. git grep returns 1
@@ -67,23 +92,23 @@ cd "$ROOT" || exit 2
 # fires the assertion. This covers checks 2 and 3 only; check 1's pathspec is
 # "." and stays non-empty from anywhere, so its wrong-directory case is covered
 # by the --show-prefix assertion above and its mistyped-pathspec case by
-# nothing.
+# nothing. Check 3's tree-wide half uses "." with exclusions and is in the
+# same position as check 1.
 n=$(git ls-tree -r --name-only HEAD -- src/ | wc -l)
 (( n > 0 )) || { echo "check-comment-refs: pathspec src/ matched no files" >&2; exit 2; }
 
-# Deliberately a superset of the sweep's own acceptance regex: the year group
-# is optional, so the three-digit form is caught as well, and the separator is
-# optional so underscores and spaces are caught alongside hyphens. Narrowing
-# this is how a whole class goes unguarded while every break-check still
-# passes.
+# Deliberately broad: the year group is optional, so the three-digit form is
+# caught as well, and the separator is optional so underscores and spaces are
+# caught alongside hyphens. Narrowing this is how a whole class goes unguarded
+# while every break-check still passes.
 ID_PAT='(TASK|ISSUE|IDEA|QUICK|RECUR)[-_ ]?(20[0-9]{2}[-_ ])?[0-9]{3,4}'
 
-# Verbatim from the sweep's enumerating pattern. Do not edit one without the
-# other. If check 3's scope is ever widened beyond src/, this text matches
-# itself through six of its alternatives and the widening must add
-# ':(exclude)testing/check-comment-refs.sh' — never an exclusion of testing/,
-# which holds real check-1 hits a directory-wide exclusion would drop.
-VOCAB_PAT='\b[RQ][0-9]\b|Category-[A-Z]|\bumbrella\b|refactor steps?|\bpre-scopes\b|R0 stub|read-isolation|cut over yet|Cutover begins|in Step [0-9]|(the|this) milestone|Milestone-'
+# VOCAB_PAT runs tree-wide. This text matches itself, so the tree-wide run
+# excludes this one file by name; never exclude testing/, which holds real
+# hits a directory-wide exclusion would drop. SRC_VOCAB_PAT is VOCAB_PAT
+# plus the alternatives that are legitimate prose outside src/.
+VOCAB_PAT='\b[RQ][0-9]\b|Category-[A-Z]|\bumbrella\b|refactor steps?|\bpre-scopes\b|R0 stub|read-isolation|cut over yet|Cutover begins|(the|this) milestone|Milestone-|[Aa]rchitectural plan|[Ff]ollow-up wiring'
+SRC_VOCAB_PAT="$VOCAB_PAT"'|in Step [0-9]|\b[Tt]his PR\b'
 
 MD_PAT='[A-Za-z0-9_./-]+\.md\b'
 
@@ -157,9 +182,12 @@ if (( ${#CITES[@]} > 0 )); then
     done < <(printf '%s\n' "${!CITES[@]}" | sort)
 fi
 
-# ── Check 3: programme vocabulary under src/ ────────────────────────────────
-rc=0
-out=$(git grep -nEI "$VOCAB_PAT" HEAD -- src/) || rc=$?
+# ── Check 3: programme vocabulary, src/ and the rest of the tree ────────────
+vocab_check() {
+    local pat=$1
+    shift
+    local rc=0 out
+    out=$(git grep -nEI "$pat" HEAD -- "$@") || rc=$?
     if (( rc > 1 )); then
         echo "check-comment-refs: check 3 grep failed (rc=$rc)" >&2
         exit 2
@@ -169,10 +197,14 @@ if [[ -n "$out" ]]; then
             | sed -E 's|^HEAD:([^:]*):([0-9]+):|\1:\2: names a plan this repository does not carry: |'
         FAILED=1
     fi
+    return 0
+}
+vocab_check "$SRC_VOCAB_PAT" src/
+vocab_check "$VOCAB_PAT" . ':(exclude)src/' ':(exclude)testing/check-comment-refs.sh'
 
 if (( FAILED != 0 )); then
     echo "" >&2
-    echo "check-comment-refs: a source comment references something a reader holding" >&2
+    echo "check-comment-refs: a comment or document references something a reader holding" >&2
     echo "only this repository cannot resolve. Rewrite the comment to say what the" >&2
     echo "code does, citing nothing outside the tree." >&2
     exit 1