fix(kb): check_okf.py flags control bytes (NUL etc.) outside \t\n\r

The validator only ever parsed frontmatter fields — it never scanned body
content, so a file with literal NUL bytes pasted in from a psql SELECT
(kb/audits/wiki-kompilat-recon-2026-08-26.md) passed silently. Adds a
whole-file scan for control bytes other than tab/newline/CR, one error per
offending line. Covered by scripts/kb/tests/test_check_okf.py.

docs/sessions/2026-08-27.md

@@ -1,23 +0,0 @@
-## Session 13:49
-
-### Commits
-a97cec0 merge: task/drobne-fixy (resolve-requests 775, prune out of health-monitor, events doc, redeploy action_id)
-1dca438 fix(supervisor): apply started_at suffix to redeploy action_id too
-40d78ce docs: fix events layout drift in CLAUDE.md
-9a86843 fix(monitor): remove unfiltered docker container prune from health-monitor.sh
-89f75c3 fix(observer): make world/resolve-requests/ group-writable
-
-### Files changed
- CLAUDE.md                                          |   2 +-
- scripts/monitor/health-monitor.sh                  | 110 +++------------------
- scripts/observer/observer.py                       |  12 +++
- services/control-plane/src/supervisor.py           |  40 ++++----
- .../control-plane/tests/test_incident_lifecycle.py |  17 ++++
- .../tests/test_supervisor_action_id_uniqueness.py  |  50 +++++++++-
- 6 files changed, 109 insertions(+), 122 deletions(-)
-
-### Deploys
-- control-plane → VPS: tagged 4/4 images `:rollback-pre-drobnefixy`, `git pull` (03441a1→a97cec0) + `docker compose up -d --build --force-recreate` (direct, no deploy-local.sh, per 26.08 precedent). Result: 4/4 healthy, zero error/traceback in logs since restart, sha256 of observer.py and supervisor.py match HEAD, `world/resolve-requests/` mode 775 confirmed, incidents.json stable (md5 unchanged) over 3 observer cycles. 30s permission test: flag `test-perms-123` dropped via plain `ssh` as `oskar` (no docker exec) was picked up and deleted in ~5s with `WARNING - Resolve-request flag for unknown incident test-perms-123 — removing flag` — 775 confirmed working in practice.
-
-### Narrative
-> _user-provided summary_