fix(framework/tools): lane-brief.sh — classify PR-body-linked issues as work-underway (#546)

Remediation of coder3 independent-validation blocker on PR #547.

lane-brief.sh inspected only the open-PR index/title/head fields, never the PR
BODY or Gitea issue linkage. A body-only "Closes #546" was therefore invisible,
so issue #546 (open, with PR #547 'Closes #546' in its body) was placed under
DISPATCH CANDIDATES with work-underway count 0 — re-dispatchable in-flight work,
unacceptable for a dispatch-truth tool.

Fix:
- Fetch open PRs as JSON including `body`; resolve PR->issue links via Gitea's
  closing-keyword set (close/closes/closed, fix/fixes/fixed, resolve/resolves/
  resolved), case-insensitive, word-boundary anchored, `#` directly following the
  keyword. Any issue so linked from an OPEN PR is classified WORK UNDERWAY.
- Preserve the prior title/head bare-ref heuristic and per-repo behavior; require
  `#` immediately after the keyword so cross-repo `owner/repo#N` forms don't leak.
- Bare `#N` prose mentions in a body are intentionally NOT links (e.g. "#538 line
  of work") to avoid marking live, dispatchable issues as in-flight.

Tests (committed, RED-on-revert non-vacuity):
- test-lane-brief-pr-linkage.sh: open-PR-with-'Closes #546'-in-body excludes #546
  from candidates (and a reverted copy with the body-scan removed regresses #546
  to a candidate — RED proof); bare #777 and substring 'hotfix #999' stay
  candidates (word-boundary + closing-keyword-only guards).
- test-ci-wait-exit-matrix.sh: ci-wait.sh exit matrix 0 (all-success) / 1
  (terminal-not-success: failure + error/killed) / 2 (usage) / 3 (timeout).

shellcheck -x + bash -n clean on all four files; no secret values. ci-wait.sh
unchanged (coder3 PASS preserved). Closed-issue exclusion unchanged.

Refs #546, PR #547

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

packages/mosaic/framework/tools/git/lane-brief.sh

@@ -65,10 +65,38 @@ ISSUES_JSON="$(tea issues list --repo "$REPO" --login "$LOGIN" --state open --li
   --fields index,title,assignees,milestone,labels --output json 2>/dev/null)" || {
   echo "FATAL: tea issues list failed for $REPO (login=$LOGIN)" >&2; exit 1; }
 
-# Open PRs, to cross-ref which issues already have work in flight.
-PRS_TSV="$(tea pulls list --repo "$REPO" --login "$LOGIN" --state open \
-  --fields index,title,head --output tsv 2>/dev/null || true)"
-PR_ISSUE_REFS="$(printf '%s\n' "$PRS_TSV" | grep -oE '#[0-9]+|[/-][0-9]{3,}' | grep -oE '[0-9]+' | sort -u || true)"
+# Open PRs, to cross-ref which issues already have work in flight. An issue is
+# "work underway" if an open PR links to it. Two link signals are honored:
+#   (a) a closing keyword in the PR BODY — Gitea's auto-close set (close/closes/
+#       closed, fix/fixes/fixed, resolve/resolves/resolved), case-insensitive,
+#       directly preceding `#N`. This is the AUTHORITATIVE link Gitea itself uses
+#       to associate a PR with the issue it resolves; a body-only "Closes #546"
+#       is the common case and MUST count. The earlier version inspected only the
+#       PR index/title/head TSV (never the body or Gitea linkage), so a body-only
+#       reference was invisible and the linked OPEN issue was misclassified as a
+#       dispatch candidate — re-dispatchable in-flight work (the #546/#547 defect).
+#   (b) a bare #N in the PR title, or an issue number embedded in the head branch
+#       (feat/546-x, fix-546) — the weaker heuristic preserved from prior behavior.
+# Bare #N mentions in the BODY are deliberately NOT treated as links: PR bodies
+# routinely name unrelated issues in prose ("relevant to the #538 line of work"),
+# and counting those would wrongly mark live, dispatchable issues as in-flight.
+# Only the closing-keyword form is a commitment to resolve that issue. Requiring
+# `#` to directly follow the keyword also keeps cross-repo `owner/repo#N` forms
+# from leaking a foreign issue number into this per-repo lane (cross-repo lanes
+# are run per-repo). JSON (not TSV) is used so multi-line bodies parse cleanly.
+PRS_JSON="$(tea pulls list --repo "$REPO" --login "$LOGIN" --state open \
+  --fields index,title,head,body --output json 2>/dev/null || echo '[]')"
+[[ -n "$PRS_JSON" ]] || PRS_JSON='[]'
+
+# \b anchors the keyword to a word start so embedded substrings do not match
+# (e.g. "prefix #5", "disclosed #7" must NOT be read as "fix #5" / "closed #7").
+GITEA_CLOSE_KW='close[sd]?|fix(e[sd])?|resolve[sd]?'
+PR_BODY_REFS="$(printf '%s' "$PRS_JSON" | jq -r '.[] | .body // ""' 2>/dev/null \
+  | grep -oiE "\\b(${GITEA_CLOSE_KW})[[:space:]:]+#[0-9]+" | grep -oE '[0-9]+' || true)"
+PR_TITLE_HEAD_REFS="$(printf '%s' "$PRS_JSON" \
+  | jq -r '.[] | [ (.title // ""), (.head // "" | if type=="object" then (.ref // "") else . end) ] | join(" ")' 2>/dev/null \
+  | grep -oE '#[0-9]+|[/-][0-9]{3,}' | grep -oE '[0-9]+' || true)"
+PR_ISSUE_REFS="$(printf '%s\n%s\n' "$PR_BODY_REFS" "$PR_TITLE_HEAD_REFS" | grep -E '^[0-9]+$' | sort -u || true)"
 
 ts="$(date -u '+%Y-%m-%d %H:%MZ' 2>/dev/null || echo '?')"
 filt="$REPO"; [[ -n "$MILESTONE" ]] && filt="$filt · milestone:'$MILESTONE'"; [[ -n "$LABEL" ]] && filt="$filt · label:'$LABEL'"