fix(pipeline): finish three changes that had only been half applied

Each of these was recorded as done and was done in one place out of two.

AR-011 -- the TransNetV2 dedup window. The derived window
(dedup_window_sec, median observed interval halved) reached scenes.json
and nothing else. SceneBoundaries, the path that actually feeds
is_scene_boundary to the tracker, kept the literal 0.04 s under a
comment claiming it "matches the dedup scenes.json applies, so the two
views agree". They did not agree. 0.04 is one frame at 25 fps and wider
than a frame at 30, so two cuts on consecutive frames merged into one
and the loss was invisible: the pipeline simply saw fewer boundaries.
The detector now supplies the window it derived.

AR-019 -- ownership. The register says ownership "comes from the
registry, not a second local tally". Both existed: promotion fired on a
local accepted-frame count and fell back to a local per-actor plurality
when the registry had not yet claimed the track. That fallback was
reachable in the live pipeline, not just in tests -- three accepted
frames arrive well before a posterior crosses the ownership threshold --
so in practice the plurality usually decided, and it could not see the
AR-025 correlation discounting it was meant to defer to. The tally is
gone; promotion now requires the registry's verdict, with the accepted
-frame count demoted to an explicit evidence floor.

AR-017 -- the route. DeadTrack carried belief but no route, and the sink
wrote the literal string "live", so a field the schema publishes could
not distinguish anything. AR-017's own verification asks for "deferred
and pooled routes distinguishable". Route is now an enum on the claim.
Only `live` occurs today; `deferred` exists so AR-020's pass has
somewhere to write instead of a serialisation change to make.

Also: TrackGallery::forget had no callers, under a comment asserting the
matcher called it "on a cut or track disappearance". The cut half was
true by another route; the disappearance half was not, so a track that
died quietly kept its diversity buffer until the next cut cleared
everything. Replaced with prune_dead against the registry's own
liveness, the same shape as the tracker's prune_boxes -- a second
opinion about which tracks exist is a second thing that can be wrong.

Removes dead logistic/logit helpers and fixes five TRACES tags that used
a comma where a pipe separates requirement types, which the gate had
been reporting as diagnostics.

TRACES: AR-011, AR-017, AR-019 | IR-002 | SR-002, SR-005

src/nodes/scene_detector_node.hpp

@@ -149,8 +149,15 @@ private:
         // final verdict. The face branch consults this for frames it has not
         // reached yet, and the watermark is what lets it tell "no boundary
         // here" from "not scored yet".
-        if (shared_ && hi > lo)
-            shared_->publish(fresh, times_[hi - 1]);
+        /// TRACES: AR-011 | SR-002
+        // Hand the join the same dedup window scenes.json uses, derived from the
+        // observed cadence rather than assumed. Set on every window because the
+        // median refines as intervals accumulate; it converges within the first
+        // window and costs a double assignment thereafter.
+        if (shared_) {
+            shared_->set_merge_window(dedup_window_sec(intervals_));
+            if (hi > lo) shared_->publish(fresh, times_[hi - 1]);
+        }
     }
 
     // At EOF the tail (< kWindow frames) never formed a full window. Pad it out
@@ -183,7 +190,10 @@ private:
         // the last full window — reach the join with no verdict and are treated
         // as boundary-free without evidence, which is precisely the ambiguity
         // the watermark exists to prevent.
-        if (shared_ && n > 0) shared_->publish(fresh, times_[n - 1]);
+        if (shared_ && n > 0) {
+            shared_->set_merge_window(dedup_window_sec(intervals_));
+            shared_->publish(fresh, times_[n - 1]);
+        }
     }
 
     void write_output() {