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_routes_retrieval_tuning.py

@@ -76,10 +76,15 @@ def test_the_route_does_not_take_the_actor_from_the_caller():
 def test_every_registry_key_is_recognised_as_a_dial():
     """Derived from the registry, both directions. A seventh surface added
     without a row here is a floor that can be written silently again."""
-    from grimoire.services.retrieval_surfaces import SURFACES, dial_for_key
+    from grimoire.services.retrieval_surfaces import (
+        SURFACES, dial_for_key, sharing_floor,
+    )
 
     for name, surface in SURFACES.items():
-        assert dial_for_key(surface.floor_key) == (name, "floor")
+        # A shared floor resolves to one of the surfaces that read it, and
+        # `set_dial` records the move on all of them.
+        owner, dial = dial_for_key(surface.floor_key)
+        assert dial == "floor" and name in sharing_floor(owner)
         assert dial_for_key(surface.budget_key) == (name, "budget")