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/gen-vault-index.py

@@ -14,6 +14,10 @@ the docs seam fails when a page is not linked from it, so it is generated:
 A page with no description is a hard error rather than an empty cell, so the
 generator cannot silently produce a silent index. Sections with no pages are
 skipped. Deterministic: the same vault always yields the same bytes.
+
+Sub-directory indices are hand-grouped (they carry curated prose), so they are
+synced rather than regenerated: dead rows dropped, row text refreshed from the
+page's description, uncovered siblings appended.
 """
 import pathlib
 import re
@@ -85,6 +89,64 @@ def section_for(page, vault, fields):
     return "Uncategorised"
 
 
+ROW = re.compile(r"^(\| )\[\[([^\]|]+)\]\]( \|)( .*?)( \|$)")
+BULLET = re.compile(r"^(- )\[\[([^\]]+)\]\]( — )(.*?)$")
+
+
+def sync_subindex(index: pathlib.Path, vault: pathlib.Path):
+    """Keep a hand-grouped sub-index honest without erasing its grouping.
+
+    Rows are locators, so their text is the linked page's own description; a
+    row whose page is gone is a dead promise and is dropped; a direct sibling
+    with no row is appended under `## Pages` (that is what the link-integrity
+    seam checks). Curated headings and prose are untouched.
+    """
+    here = index.parent
+    known = {p.stem for p in here.rglob("*.md")
+             if ".AGENTTRASH" not in str(p) and p.name != "index.md"}
+    lines = index.read_text().split("\n")
+    out, dropped, refreshed = [], 0, 0
+    for line in lines:
+        for pat, wrap in ((ROW, "| [[{}]] |{} {} |"), (BULLET, "- [[{}]] — {}")):
+            m = pat.match(line)
+            if not m:
+                continue
+            stem = m.group(2).strip()
+            if stem not in known:
+                dropped += 1
+                line = None
+                break
+            cand = next((p for p in here.rglob(f"{stem}.md")
+                         if ".AGENTTRASH" not in str(p)), None)
+            desc = frontmatter_fields(cand.read_text(errors="replace")).get("description") \
+                if cand else None
+            if desc:
+                current = m.group(4).strip()
+                if current != desc:
+                    line = wrap.format(stem, " " if pat is ROW else "", desc) \
+                        if pat is ROW else wrap.format(stem, desc)
+                    refreshed += 1
+            break
+        if line is not None:
+            out.append(line)
+    text = "\n".join(out)
+    # Presence must be the wikilink itself: a bare stem is a substring of other
+    # page names (`frank-medium` lives inside `frank-medium-rocmfpx`), and a
+    # sibling matched that way silently never gets a row.
+    missing = sorted(
+        (p.stem, frontmatter_fields(p.read_text(errors="replace")).get("description", ""))
+        for p in here.glob("*.md")
+        if p.name != "index.md" and f"[[{p.stem}]]" not in text
+    )
+    if missing:
+        block = ["", "## Pages", "", "| Page | Owns |", "|---|---|"]
+        block += [f"| [[{stem}]] | {desc} |" for stem, desc in missing]
+        text = text.rstrip("\n") + "\n" + "\n".join(block) + "\n"
+    if text != index.read_text():
+        index.write_text(text)
+    return dropped, refreshed, len(missing)
+
+
 PIPELINE_SECTION_DIR = "Pipeline Parallelism"
 
 
@@ -127,7 +189,16 @@ def main(argv):
         out.append("")
     out.append("<!-- generated by scripts/gen-vault-index.py; edit page frontmatter instead -->")
     index.write_text("\n".join(out) + "\n")
-    print(f"{index}: {sum(len(v) for v in buckets.values())} rows in {len([t for t in ORDER if buckets.get(t)])} sections")
+    touched = 0
+    for sub in sorted(vault.rglob("index.md")):
+        if sub == index:
+            continue
+        dropped, refreshed, added = sync_subindex(sub, vault)
+        if dropped or refreshed or added:
+            touched += 1
+            print(f"  {sub}: -{dropped} dead rows, {refreshed} refreshed, +{added} added")
+    print(f"{index}: {sum(len(v) for v in buckets.values())} rows in "
+          f"{len([t for t in ORDER if buckets.get(t)])} sections, {touched} sub-indices synced")
     return 0