test(redos): one CPU clock for every bound, and a second row measured dead

`5667063` moved test_output.py's ReDoS bounds off the wall clock, because a
loaded machine steals wall seconds without adding any cycles and two rows
failed at 2.24s / 3.66s against a 2.0s bound while census had the CPU. The
remaining ten bounds in five other files still ran on `time.monotonic()` and
carried the same defect. They now share ONE clock.

The clock is IMPORTED, not copied: `tests/redos_clock.py`. Five private copies
would leave four of them unpinned -- the instrument test
(test_the_redos_clock_ignores_time_this_process_did_not_spend) can only pin the
implementation it calls, and the suite already holds that rule for the code it
measures.

Every ported row was verified the only way a time bound can be: the vulnerable
form patched back in, red demanded, `git checkout --` after. Measured against
the 2.0s bound (3.0s for the url arm):

  active_content long-attr   `{0,63}` -> `*`        RED
  neutralize     long-attr   same patch             RED
  output gate    long-attr   same patch             12.41s
  okf link graph  `[^\]\[]` -> `[^\]]`               6.91s
  sanitize comment  str.find -> `<!--.*?-->`        17.56s
  lexicon md-link-anchor-text                      319.14s
  lexicon md-link-anchor-url                         8.55s
  lexicon md-link-ref-comment                       37.82s

Two rows did not go red, for two different reasons.

test_sanitize.py::test_legitimate_comment_heavy_document is the legitimate SIDE
of a separation, not a second pin on the defect: closed comments never withhold
the required literal, so the lazy form runs it in 0.016s. Recorded in place.

test_lexicon.py::test_redos_pathological_subagent_input_returns_fast is DEAD --
the same zero-signal shape the `<a ` carrier had, found by the same method. The
seed form is `(?:.*?\s+)?` (llm-security 7.8.0, injection-patterns.mjs:84) and
this repo has never carried it: the bounded `{0,12}?` port is in the pattern
table's first commit. Patched in by hand at the row's own size: shipped 0.135s
vs seed 0.113s, separation 1.2x. Not the keyword gate either -- a variant that
reaches the inner branch stays linear over four doublings (exponent ~1.0),
because the nesting is one lazy run inside an OPTIONAL group, never a repeated
one. Left standing with the measurement written into it; picking a new carrier
is an operator call, like the wall-clock row above it.

The dead sibling row named in STATE is fixed: test_active_content.py's
long-attribute row swaps carrier `<a ` -> `<script `, for the reason `5667063`
established on its composed-gate twin -- 0.7.0's own no-URL narrowing put `<a>`
in `_URL_AFFORDANCE_TAGS`, so the tag returns inert BEFORE its body reaches the
arm the row guards. Re-measured here, not inherited: `<a ` 0.041s and NO
findings against the vulnerable form; `<script ` 19.349s against 0.052s
shipped, 373x apart.

`test_pathological_input_returns_within_a_bound` deliberately keeps its wall
clock (operator decision): it claims to catch a hang, and only a wall clock
catches one.

792 tests, 129/129, 6/6.

tests/test_okf.py

@@ -17,8 +17,6 @@ OKF spec facts used here (verified against okf/SPEC.md, 2026-07-06):
 """
 import pytest
 
-import time
-
 from llm_ingestion_guard.okf import (
     parse_frontmatter,
     scan_concept,
@@ -41,6 +39,7 @@ from llm_ingestion_guard.okf import (
 from llm_ingestion_guard.report import Report
 from llm_ingestion_guard.disposition import Trust, Disposition, PRESET_USER_UPLOAD
 from llm_ingestion_guard import screen_output
+from redos_clock import scan_seconds
 
 
 # --- happy path: split + parse the minimal flat subset -----------------------
@@ -676,9 +675,7 @@ _LINK_REDOS_N = 100_000
 
 
 def test_crafted_link_payload_stays_bounded():
-    start = time.monotonic()
-    extract_link_targets("[" * _LINK_REDOS_N)
-    assert time.monotonic() - start < 2.0
+    assert scan_seconds(extract_link_targets, "[" * _LINK_REDOS_N) < 2.0
 
 
 # The destination run behind the label gets no row: `[^)\s]+` needs only one