refactor(lint): cache manifest parsing, single-pass size check

Two more efficiency findings from the same code-review pass:

- check-vale-style-sync.sh's hook_file_regexes() reparsed both
  pre-commit manifests from scratch on every call. The final
  validation loop calls it once per probe (3 probes: skill-audit once,
  agent-audit twice for its two file shapes), so agent-audit's regex
  set was being parsed twice for no reason. Now cached per skill in a
  lazily-populated associative array, with a separate "seen" map so an
  empty result isn't mistaken for "not yet computed."
- skill-size-check.sh read the target file twice (separate awk and
  wc -w calls) to get line and word counts; now a single awk pass
  returns both. Also documented, next to MAX_LINES/MAX_WORDS, why
  those constants are duplicated against skill-audit/scripts/
  validate.sh's Python implementation rather than unified — same
  cross-language/cross-context tradeoff as vale-wrap.sh's duplication,
  guarded by tests/test-skill-size-check.sh's drift check.

Verified: test-check-vale-style-sync.sh 20/20, test-skill-size-check.sh
9/9, full suite 12/12, pre-commit --all-files clean.

scripts/check-vale-style-sync.sh

@@ -80,26 +80,45 @@ done
 # Prints the `files:` regex of every hook, in either manifest, whose entry is
 # $1's vale-wrap.sh. Records are delimited by their `- id:` line, so the check
 # does not depend on `entry:` preceding `files:` within a record.
+#
+# Cached per skill (in HOOK_REGEX_CACHE, populated lazily) because the final
+# validation loop below probes agent-audit twice — once for its CC agent-file
+# shape, once for its Copilot .agent.md shape — and both probes need the same
+# regex set. Without the cache, that pair of calls would each re-parse both
+# manifest files from scratch for no new information. HOOK_REGEX_CACHE_SEEN is
+# a separate array so a skill with no matching hooks (empty result) is still
+# recognized as already computed, rather than re-parsed every call.
+declare -A HOOK_REGEX_CACHE=()
+declare -A HOOK_REGEX_CACHE_SEEN=()
 hook_file_regexes() {
-  local skill="$1" manifest raw
-  for manifest in "$REPO_ROOT/.pre-commit-hooks.yaml" "$REPO_ROOT/.pre-commit-config.yaml"; do
-    [[ -f "$manifest" ]] || continue
-    awk -v skill="$skill" '
-      function flush() {
-        if (entry ~ skill "/scripts/vale-wrap.sh" && files != "") print files
-        entry = ""; files = ""
-      }
-      /^[ \t]*-[ \t]*id:/ { flush() }
-      /^[ \t]*entry:/ { entry = $0 }
-      /^[ \t]*files:/ { files = $0; sub(/^[ \t]*files:[ \t]*/, "", files) }
-      END { flush() }
-    ' "$manifest"
-  done | while IFS= read -r raw; do
-    # Strip the surrounding YAML quotes; the regex itself never carries them.
-    raw="${raw%\'}"; raw="${raw#\'}"
-    raw="${raw%\"}"; raw="${raw#\"}"
-    printf '%s\n' "$raw"
-  done
+  local skill="$1" manifest raw result
+  if [[ -n "${HOOK_REGEX_CACHE_SEEN[$skill]:-}" ]]; then
+    printf '%s' "${HOOK_REGEX_CACHE[$skill]}"
+    return
+  fi
+  result="$(
+    for manifest in "$REPO_ROOT/.pre-commit-hooks.yaml" "$REPO_ROOT/.pre-commit-config.yaml"; do
+      [[ -f "$manifest" ]] || continue
+      awk -v skill="$skill" '
+        function flush() {
+          if (entry ~ skill "/scripts/vale-wrap.sh" && files != "") print files
+          entry = ""; files = ""
+        }
+        /^[ \t]*-[ \t]*id:/ { flush() }
+        /^[ \t]*entry:/ { entry = $0 }
+        /^[ \t]*files:/ { files = $0; sub(/^[ \t]*files:[ \t]*/, "", files) }
+        END { flush() }
+      ' "$manifest"
+    done | while IFS= read -r raw; do
+      # Strip the surrounding YAML quotes; the regex itself never carries them.
+      raw="${raw%\'}"; raw="${raw#\'}"
+      raw="${raw%\"}"; raw="${raw#\"}"
+      printf '%s\n' "$raw"
+    done
+  )"
+  HOOK_REGEX_CACHE[$skill]="$result"
+  HOOK_REGEX_CACHE_SEEN[$skill]=1
+  printf '%s' "$result"
 }
 
 # Asks vale — the thing that actually applies these globs — whether a config

scripts/skill-size-check.sh

@@ -35,6 +35,13 @@ set -euo pipefail
 # tokenization and does not replace one. Re-measure the corpus before treating
 # any of these numbers as still current.
 
+# These constants are intentionally duplicated in
+# skill-audit/scripts/validate.sh (Python) rather than shared from one file:
+# this script is a standalone bash pre-commit hook, that one is an in-skill
+# Python validator invoked in a different context (same rationale as
+# vale-wrap.sh's per-plugin duplication — see its own header comment).
+# tests/test-skill-size-check.sh asserts both files agree on these values, so
+# drift between them fails CI rather than silently diverging.
 MAX_LINES=500
 MAX_WORDS=2770
 FAIL=0
@@ -42,16 +49,19 @@ FAIL=0
 for f in "$@"; do
   [[ -f "$f" ]] || continue
 
-  # awk's NR counts the final line even without a trailing newline, matching
-  # Python's splitlines() semantics (used by skill-audit/scripts/validate.sh
-  # for its own line count) — `wc -l` undercounts by 1 in that case.
-  lines=$(awk 'END{print NR}' "$f")
+  # Single awk pass computes both line count and word count, avoiding a
+  # second read of the file. NR counts the final line even without a
+  # trailing newline, matching Python's splitlines() semantics (used by
+  # skill-audit/scripts/validate.sh for its own line count) — `wc -l`
+  # undercounts by 1 in that case. Word count uses awk's default
+  # whitespace-splitting NF, matching `wc -w` semantics.
+  read -r lines words <<< "$(awk '{w += NF} END{print NR, w+0}' "$f")"
+
   if (( lines > MAX_LINES )); then
     echo "ERROR: $f has $lines lines, exceeding the $MAX_LINES-line ceiling (agentskills.io skill-authoring.md)" >&2
     FAIL=1
   fi
 
-  words=$(wc -w < "$f")
   if (( words > MAX_WORDS )); then
     echo "ERROR: $f has $words words (proxy for tokens), exceeding the $MAX_WORDS-word ceiling (~5,000 tokens, agentskills.io skill-authoring.md)" >&2
     FAIL=1