feat(scripts): OKF conformance linter, trash-aware vault seams

Add scripts/check-okf.py: enforces the OKF v0.1 hard rules the repo had
been carrying by convention — parseable frontmatter with type/title/
description/timestamp, description shape (length, not-equals-title, no
restated quantity), the reserved-name and index.md rules, log.md's date
heading shape (bare ISO date, one entry per date, newest first), the
500-line hint, and the doubled-page signature (a second `type:` key in
the body). Citations are reported as a soft tally, not a failure. The
500-line ceiling is escapable two ways, both explainable: `okf-exempt:
length` in a page's own frontmatter, and pages derived as one-per-
endpoint — live endpoints from scripts/, retired-endpoint era pages from
their tag (AGENTS.md lets a campaign ledger live on the page that
measured it).

scripts/gen-vault-index.py: sibling-presence was tested as a bare stem
substring, so a page whose name is a prefix of another page's name
(`frank-medium` inside `frank-medium-rocmfpx`) silently never got an
index row. Test the wikilink form instead.

scripts/check-vault-links.py: `.AGENTTRASH` is deleted-but-held state,
not vault content. It is now excluded from both the scan set and the
target index, so a live link into the trash reads as unresolved instead
of resolved.

tests/docs_completeness.bats: the same exclusion in both page walks —
trashed pages need no index row, and a trashed page must not satisfy the
docs requirement for a live compose service. Adds the OKF conformance
and index-freshness tests.

scripts/port-census.py: the port-before-cut orphan census used to prove
a merge lost no fact, kept so the next collapse can re-run it.

scripts/port-census.py

@@ -0,0 +1,78 @@
+#!/usr/bin/env python3
+"""Port census: prove a merge/collapse lost no fact.
+
+For every line that existed in the OLD set and not in the NEW set, check that
+each of its significant tokens (numbers, long identifiers, paths) still occurs
+somewhere in the NEW corpus. A line whose every token survives is a reworded
+line; a line with an unheld token is a candidate fact loss and gets printed.
+
+  port-census.py <new-glob-dir> <old-file> [<old-file> ...]
+
+Old files may be `git-rev:path` (read from git) or a path (e.g. a trash copy).
+"""
+import pathlib
+import re
+import subprocess
+import sys
+
+
+def toks(line):
+    out = []
+    for n in re.findall(r"\d[\d,]*(?:\.\d+)?", line):
+        if len(n.replace(",", "").split(".")[0]) >= 3 or (
+            "." in n and len(n.split(".")[-1]) >= 2 and len(n.replace(",", "")) >= 4
+        ):
+            out.append(n)
+    # Identifiers, flags, paths and backticked spans are the facts worth
+    # tracking; ordinary prose words are not — they reword on every rewrite.
+    out += [w for w in re.findall(r"[A-Za-z][\w./:-]{7,}", line)
+            if re.search(r"[\d_.:/-]", w) or w.isupper()]
+    out += [s.strip() for s in re.findall(r"`([^`]+)`", line) if len(s) > 3]
+    return out
+
+
+def held(tok, corpus):
+    t = tok.replace(",", "")
+    alt = rf"\b{re.escape(t)}\b"
+    for c in corpus:
+        if tok in c or t in c:
+            return True
+        if re.search(alt, c.replace(",", "")):
+            return True
+    return False
+
+
+def main(argv):
+    new_dir = pathlib.Path(argv[1])
+    corpus = [
+        p.read_text(errors="replace")
+        for p in new_dir.rglob("*.md")
+        if ".AGENTTRASH" not in str(p) and ".obsidian" not in str(p)
+    ]
+    blob = "\n".join(corpus)
+    lost = 0
+    checked = 0
+    for spec in argv[2:]:
+        if spec.startswith("git-"):
+            ref, path = spec[4:].split(":", 1)
+            old = subprocess.run(["git", "show", f"{ref}:{path}"],
+                                 capture_output=True, text=True).stdout
+            label = f"{ref}:{path}"
+        else:
+            old = pathlib.Path(spec).read_text(errors="replace")
+            label = spec
+        for line in old.splitlines():
+            s = line.strip().strip("->*|# ").strip()
+            if len(s) < 30 or s.startswith("```"):
+                continue
+            checked += 1
+            missing = [t for t in toks(s) if not held(t, [blob])]
+            if missing:
+                lost += 1
+                print(f"  {label}\n    L: {s[:150]}\n    unheld: {', '.join(missing[:6])}")
+    print(f"{checked} old lines checked, {lost} with unheld tokens")
+    return 1 if lost else 0
+
+
+if __name__ == "__main__":
+    sys.exit(main(sys.argv))