fix(kaizen): scope still_exists to repo paths; test age nudge; tidy --today

- Add REPO_DIRS constant; still_exists now only checks tokens that start
  with a known repo top-level dir, ignoring plugin names (caddy-dns/gandi),
  make command fragments (tf-init/plan), and role-relative paths.
- Add test_still_exists_ignores_non_repo_tokens (was failing before fix).
- Add test_nudge_line_overdue_on_age to close coverage gap on age threshold.
- Add load_signals docstring.
- Replace manual --today date parsing with datetime.date.fromisoformat type
  converter so malformed dates give a clean argparse error.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

scripts/friction-scan.py

@@ -21,6 +21,10 @@ NUDGE_MIN_OPEN = 8
 NUDGE_MAX_AGE_DAYS = 21
 NUDGE_MIN_RECURRENCE = 3
 
+# Top-level repo dirs — only tokens under these are treated as repo-root paths
+# for still_exists (avoids false negatives on plugin names, make commands, etc.).
+REPO_DIRS = ("roles/", "scripts/", "docs/", "playbooks/", "inventories/", "tests/", "terraform/", ".claude/")
+
 TAG_RE = re.compile(r"`\[(friction|gotcha|recurring|unused)\]`")
 DATE_RE = re.compile(r"(\d{4})-(\d{2})-(\d{2})")
 ORDINAL_RE = re.compile(r"(\d+)(?:st|nd|rd|th)\s+(?:occurrence|reinforcement|time)", re.I)
@@ -106,7 +110,8 @@ def parse_signal(raw, today):
         first_seen = None
         age_days = None
     paths = parse_paths(raw)
-    still_exists = all(os.path.exists(os.path.join(REPO_ROOT, p)) for p in paths) if paths else True
+    repo_paths = [p for p in paths if p.startswith(REPO_DIRS)]
+    still_exists = all(os.path.exists(os.path.join(REPO_ROOT, p)) for p in repo_paths) if repo_paths else True
     return {
         "tag": tag_m.group(1) if tag_m else None,
         "first_seen": first_seen,
@@ -119,6 +124,7 @@ def parse_signal(raw, today):
 
 
 def load_signals(path, today):
+    """Read a FRICTION.md file and return its Open signals as parsed dicts."""
     with open(path, encoding="utf-8") as fh:
         text = fh.read()
     return [parse_signal(s, today) for s in split_signals(extract_open_section(text))]
@@ -137,16 +143,12 @@ def nudge_line(signals):
 def main():
     parser = argparse.ArgumentParser(description="Parse FRICTION.md Open signals for /kaizen.")
     parser.add_argument("--nudge", action="store_true", help="print a one-line overdue summary")
-    parser.add_argument("--today", help="override today's date (YYYY-MM-DD) for testing")
+    parser.add_argument("--today", type=datetime.date.fromisoformat,
+                         help="override today's date (YYYY-MM-DD) for testing")
     parser.add_argument("--file", default=FRICTION, help="path to FRICTION.md")
     args = parser.parse_args()
 
-    if args.today:
-        y, m, d = args.today.split("-")
-        today = datetime.date(int(y), int(m), int(d))
-    else:
-        today = datetime.date.today()
-
+    today = args.today or datetime.date.today()
     signals = load_signals(args.file, today)
     if args.nudge:
         print(nudge_line(signals))

tests/test_friction_scan.py

@@ -110,6 +110,16 @@ def test_nudge_line_overdue_on_count():
     assert "OVERDUE" in fs.nudge_line(sigs)
 
 
+def test_still_exists_ignores_non_repo_tokens():
+    sig = fs.parse_signal("`[gotcha]` **x** (2026-06-01): `caddy-dns/gandi` and `make tf-init/plan`", TODAY)
+    assert sig["still_exists"] is True
+
+
+def test_nudge_line_overdue_on_age():
+    sigs = [{"age_days": 21, "recurrence_count": 1}]
+    assert "OVERDUE" in fs.nudge_line(sigs)
+
+
 def test_load_signals_reads_real_friction_file():
     path = os.path.join(os.path.dirname(__file__), "..", "docs", "FRICTION.md")
     sigs = fs.load_signals(path, TODAY)