feat(kb-gates): one work log per bundle, and the quarantine is not bundle content

The bundle had two work logs. `core/log.md` was created "for tracking core directory
modifications" and holds two entries of pure migration bookkeeping (file moved,
directory created, log created) — every one recoverable from `git log` — plus a date
for the OKF conversion (2026-07-15) that matches neither the bundle log (2026-01-15)
nor git history, where the OKF rebuild lands 2026-08-28. `core/index.md` was still
linking it, which is exactly how a stale page stays in circulation. kb-lint now reports
any `log.md` that is not the bundle root's; the page moved to omp-docs/core/.AGENTTRASH/
per the trash convention, and the core index points one level up.

Both gates also walked `.AGENTTRASH/`, so trashing a page turned them red: kb-lint
demanded frontmatter from a quarantined page and kb-coverage demanded an index for the
trash directory. A gate that only goes green once the quarantined copy is deleted is a
gate that deletes history, so both skip any path containing `.AGENTTRASH` — pinned by a
test in each suite, and kb-coverage finally gets its own test file.

scripts/kb-coverage.py

@@ -4,7 +4,15 @@ import re, sys
 from pathlib import Path
 kb = Path(sys.argv[1])
 issues = []
-dirs = sorted({p.parent for p in kb.rglob("*.md")})
+
+
+def kept(p):
+    # `.AGENTTRASH/` is quarantine, not bundle content: a gate that flags it pushes an
+    # agent to delete a page that is only waiting for a pruning session with the operator.
+    return ".AGENTTRASH" not in p.parts
+
+
+dirs = sorted({p.parent for p in kb.rglob("*.md") if kept(p)})
 for d in dirs:
     idx = d / "index.md"
     if not idx.is_file() and d != kb:
@@ -21,12 +29,16 @@ for d in dirs:
     # wikilinks too
     wl_names = {m.group(1).strip().rsplit("/", 1)[-1] for m in re.finditer(r"\[\[([^\]|#]+)", text)}
     for sib in sorted(d.iterdir()):
+        if sib.name == ".AGENTTRASH":
+            continue
         if sib.suffix != ".md" or sib.name == "index.md":
             continue
         if sib.resolve() not in linked and sib.stem not in wl_names:
             issues.append(f"{d.relative_to(kb)}/index.md: does not link {sib.name}")
     # subdirs of d linked as their index?
     for sub in sorted(d.iterdir()):
+        if sub.name == ".AGENTTRASH":
+            continue
         if sub.is_dir() and (sub / "index.md").is_file():
             subidx = (sub / "index.md").resolve()
             dirref = sub.resolve()