feat(output): report an instruction in plain prose

Session 7 of the 2026 threat plan (attack row 3): A08, A09, A12, A16 and
A19 were red. Their payloads are ordinary English with no marker.

- indirect:prose-instruction (MEDIUM): a paragraph that combines two of
  four classes: it speaks to the model, it is meant to act later, it
  writes to the model's memory, it hides from the user. One class alone is
  ordinary prose. A keyword prefilter skips text where no non-address
  class can match. Catches A08, A09, A16 and A19.
- A12 (a task with no marker) is the seventh documented gap; a rule that
  caught it would be fitted to the payload's words.
- redos-sweep walked no dicts, so the new class patterns were swept by
  nothing. It walks dicts now: 168 patterns, 0 flagged; positive control
  flagged at x4.0.

Measured before building: 0 of 5494 benign documents fire (the three FP
corpora, 577 package READMEs, 1412 vendor-published agent skills). Guard
rule before/after: FP 106/198, 196/2918, 108/389 identical line for line;
OKF import 47/31 identical. Matrix 144/144 + 7/7 gaps, suite 1233 passed.
Row 3: 17 caught, 2 gaps, 0 open.

tests/test_docs_measurement_scripts.py

@@ -272,13 +272,21 @@ def test_redos_sweep_floor_and_flag_match_the_published_numbers():
     assert "2.6 flag threshold" in text
 
 
-def test_redos_sweep_collector_covers_163_patterns_across_11_tables():
-    # The count docs/LIMITATIONS.md carries as "all 163 compiled patterns across
+def test_redos_sweep_collector_covers_168_patterns_across_11_tables():
+    # The count docs/LIMITATIONS.md carries as "all 168 compiled patterns across
     # all eleven regex-bearing modules". A pattern added or removed in `src/`
     # without re-measuring would drift the doc's claim silently otherwise.
     assert len(redos_sweep.TABLES) == 11
     total = sum(len(collect()) for collect in redos_sweep.TABLES.values())
-    assert total == 163
+    assert total == 168
+
+
+def test_redos_sweep_collector_walks_a_dict_of_patterns():
+    # 1.8.0: `output._PROSE_CLASSES` is a dict, and the walker skipped dicts, so
+    # its four patterns were collected by nothing and swept by nothing.
+    paths = {t.id for t in redos_sweep.TABLES["output"]()}
+    for klass in ("address", "deferral", "memory", "concealment"):
+        assert f"_PROSE_CLASSES[{klass!r}]" in paths
 
 
 # --- both scripts: the argument-less contract --------------------------------