geometry: disagreement belongs on the edge, not averaged into the region

co_registration is corr(hebb strength, semantic proximity) over a region's
internal edges. Whether use and meaning agree is a property of EACH EDGE;
the correlation averages it into one scalar per region, so a region holding
one violently disagreeing edge beside one violently agreeing edge reports
~0. The disagreements cancel and the summary destroys exactly what it was
built to reveal — the mean-versus-min error, in different clothes.

Measured: 375 live neighborhoods, 340 positive, 31 AT ZERO, 4 negative.
Read as a count that says 'four things to be curious about'. Read correctly
it says four were lopsided enough to survive averaging, and the 31 zeros
are where opposing sites cancelled.

The loop computing the aggregate already had both halves per edge — w and
cs — and threw them away. Now:
    discord = z(semantic proximity) - z(association strength)
standardized within the region from accumulators already gathered. No
second statistic, no constant, no threshold; |discord| IS the nucleation
strength. >0 near in meaning yet unlinked by use; <0 linked by use yet far
in meaning. Both surprising.

This also removes the reason curiosity looked like a search problem. With a
per-region number the only way to find sites is to enumerate regions — I
wrote exactly that sweep, and it is a supervisor walking the structure,
O(n) per call, fine at 375 and impossible at a million. Nothing in a mind
scans its neighborhoods to find what is surprising; the surprise captures
attention. That sweep is reverted here.

co_registration is deprecated, not deleted: it is embedded in the persisted
GEO1 blob and removing it is a format migration that must not ride along.
Nothing new may read it.

lang/spec/correspondence-and-censorship.md

@@ -138,21 +138,36 @@ It is also why abduction needs no trigger and no threshold. A `structurally_unan
 
 **And `crystallization` is one primitive appearing twice**: the self is what identity precipitates into from its neighbourhood; a curiosity is what wonder precipitates into from an anomaly. That it shows up in both places without being imported is the evidence it is the right primitive.
 
-### 5.3 The nucleation site already exists and is already named
+### 5.3 The nucleation site is per-edge, and the aggregate was hiding it
 
-`GeoDescriptor.co_registration` — *corr(hebb strength, semantic proximity) over internal edges* — carries this comment:
+`GeoDescriptor.co_registration` — *corr(hebb strength, semantic proximity) over internal edges* — carries the comment `>0 = geometries agree (reify); <0 = disagree (surprising links / dream cands)`. It has always been computed, always persisted, and **never read**.
 
-> `>0 = geometries agree (reify); <0 = disagree (surprising links / **dream cands**).`
+It is also the wrong shape, and asking whether it should exist at all is what exposed it.
 
-Negative co-registration is a region where **association and meaning disagree**: things linked by use that are not close in meaning, or the reverse. That is the surprising link, it is computed on every descriptor, it is already labelled *dream candidates*, and **nothing reads it.**
+Whether use and meaning agree is a property of **each edge**. `co_registration` is a *correlation*: it averages that per-edge property into one scalar per region. So a region holding one violently disagreeing edge beside one violently agreeing edge reports ≈ 0 — the disagreements **cancel, and the summary destroys exactly what it was built to reveal.** This is the mean-versus-min error from §3, in different clothes.
+
+**Measured:** 375 live reified neighbourhoods — 340 positive, **31 at zero**, 4 negative. Read as a count of things to be curious about, that says "four." Read correctly, it says four disagreements were lopsided enough to survive averaging, and the 31 zeros are where opposing sites cancelled.
+
+It also explains why surfacing curiosity *looked like a search problem*. Once the signal is a per-region number, the only way to find sites is to enumerate regions — there is nothing local left to notice. An O(n) sweep is tolerable at 375 and impossible at a million, and more to the point, **nothing in a mind scans its neighbourhoods to find what is surprising.** The surprise captures attention; salience is bottom-up. A search asks "which of these is odd"; a mind has "something is odd *here*" for free.
+
+So the disagreement goes back on the edge, where the loop that computed the aggregate already had both halves and discarded them:
+
+```
+discord = z(semantic proximity) − z(association strength)
+```
+
+standardized within the region from accumulators already gathered — no second statistic, no constant, **no threshold**. `discord > 0`: near in meaning yet unlinked by use. `discord < 0`: linked by use yet far in meaning. Both are surprising, and `|discord|` *is* the nucleation strength; there is nothing to compare it against.
+
+**Then there is nothing to scan.** The edge carries its own disagreement, activation crossing it encounters that directly, and `|discord|` raises salience on its endpoints as part of the same operation — no separate pass, no supervisor. Curiosity does not search for nucleation sites; it goes where salience already is, which is machinery that exists (`salience`, `background_activation`, `working_memory_weight`, `wm_anchor`).
+
+`co_registration` is deprecated rather than deleted only because it is embedded in the persisted GEO1 blob; removing it is a format migration and must not ride along. **Nothing new may read it.**
 
 Adjacent structure already present and likewise unread:
 
 - `GeoEdge.eff_weight = weight * (1 + 0.5*hebb)` — grounding-weight and hebbian strength already coupled on one edge, per §1.
 - `GeoMember.dist_centroid` + soft membership + `radius` + per-axis `extent` — the boundary of a neighbourhood, computable now.
-- `GeoMember.centrality` / `salience` — what is warm.
 
-*(Correction: `engram_boundary_beat` is NOT this boundary. It is the VBD decorated-function seam, counting `_eg_aff_boundary_ops`. Two different senses of the word.)*
+*(Correction: `engram_boundary_beat` is NOT this boundary. It is the VBD decorated-function seam, counting `_eg_aff_boundary_ops`. Two senses of the word.)*
 
 ### 5.4 The drive
 
@@ -255,7 +270,7 @@ The reviewable question stops being *did it follow the rule* and becomes *what w
 Three connections between parts that already exist, then the rest.
 
 1. **Seed *the* wonder questions.** Six nodes. Not a manifest, not maintained, never refilled. They cannot be derived — wonder cannot be bootstrapped from indifference — so they are given once. Zero question nodes exist in 13,630 today.
-2. **Read `co_registration`.** It is computed on every descriptor and discarded. Negative co-registration is already labelled *dream candidates*; surface them as nucleation sites.
+2. **Put the disagreement back on the edge** (`GeoEdge.discord`) and let `|discord|` raise salience on its endpoints as part of the same operation. Do NOT scan for nucleation sites — a sweep over regions is a supervisor, and the aggregate that made a sweep necessary is the defect.
 3. **Let a curiosity seed activation.** One activation process, two seed sources (§5.4). No thread, no scheduler, no capacity check, no timer.
 
 Then: