align(4909d): every rule arm that annotates reads one bar, kb_rule_threshold at 0.70

prompt_rule, pre_tool_rule and write_path_rule now share one settings key,
RULE_FLOOR_KEY = "kb_rule_threshold", default 0.70. The reply backstop keeps
its own 0.80, because there the floor is a stop bar. Moving the shared floor
through tune_retrieval or the Settings form records a tuning event on every
surface that reads it (set_dial, via retrieval_surfaces.sharing_floor), and
the result names the surfaces it carried as `moved_with`. Settings shows one
"Standing-rule confidence threshold" control where it showed three.

Operator ruling (2026-10-05): one shared bar for the rule arms, "especially
since we're only taking the first x number of them" -- the budget limits
what is shown; the bar only decides what is worth ranking. Kept a dial.

Why 0.70, from records read rather than percentiles:
- write_path_rule near-misses at 0.7199-0.72 were all false positives
  (rule 149 against a Lidarr comment, 157 against a retention Svelte file,
  121 against an Archives restore, 164 against a config test, 131 against a
  Go package), so the old 0.72 was not hiding real hits -- but the band does
  noise control on this arm, so dropping 0.02 costs little.
- prompt_rule: the operator set 0.70 by hand on 2026-09-18, after a 0.60
  experiment admitted junk and was reverted. 0.70 is the number with a human
  decision behind it.
- pre_tool_rule lines near 0.68 this session were mostly noise; rising to
  0.70 trims them, and the band still narrows what clears.

Retired keys: kb_promptrule_threshold, kb_toolrule_threshold and
kb_rulehint_threshold are no longer read. Rows an install stored under them
stay in the settings table, inert. On this instance the effective bars move
pre_tool_rule 0.68 -> 0.70, write_path_rule 0.72 -> 0.70, prompt_rule stays
0.70; record_release_defaults writes those per-surface release rows on boot,
so the telemetry shift has an event to explain it.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

tests/test_retrieval_surfaces.py

@@ -71,13 +71,29 @@ def test_every_surface_name_is_a_real_telemetry_source():
     )
 
 
-def test_no_two_surfaces_share_a_settings_key():
-    """One dial, one label."""
-    floors = [s.floor_key for s in rs.SURFACES.values()]
+def test_a_shared_settings_key_is_one_bar_with_one_default():
+    """One dial, one label. Surfaces may share a floor key, as the rule arms
+    do, but then they must ship the same default: otherwise the one number
+    means something different on each surface until somebody sets it."""
+    by_key: dict[str, set[float]] = {}
+    for s in rs.SURFACES.values():
+        by_key.setdefault(s.floor_key, set()).add(s.floor_default)
+    split = {k: v for k, v in by_key.items() if len(v) > 1}
+    assert not split, f"a shared floor key ships two defaults: {split}"
+
     budgets = [s.budget_key for s in rs.SURFACES.values()]
-    assert len(set(floors)) == len(floors), f"duplicate floor key in {floors}"
     assert len(set(budgets)) == len(budgets), f"duplicate budget key in {budgets}"
-    assert not (set(floors) & set(budgets)), "a floor key doubles as a budget key"
+    assert not (set(by_key) & set(budgets)), "a floor key doubles as a budget key"
+
+
+def test_the_rule_arms_that_annotate_share_one_bar_and_the_reply_stop_does_not():
+    from grimoire.services.retrieval_pipeline import RULE_FLOOR_KEY
+
+    assert sorted(rs.sharing_floor("prompt_rule")) == [
+        "pre_tool_rule", "prompt_rule", "write_path_rule",
+    ]
+    assert rs.SURFACES["prompt_rule"].floor_key == RULE_FLOOR_KEY
+    assert rs.sharing_floor("reply_rule") == ["reply_rule"]
 
 
 def test_every_surface_says_what_it_asks_over_what_and_how_often():