feat(content): give the specimen a never-gated core secret

The purge left `gate: never` — the rung no disposition unlocks — demonstrated
nowhere. Duncarrow's Crell chain had taught it; specimen.md only taught `warm`.

Adds secret.specimen-drowned-clerk (secrecy 4, gate: never), so the specimen
now shows an ascending 2 -> 4 chain and a reason `never` exists: the NPC holds
it, but saying it aloud would hang him. Mirrored in the skill's worked example,
which now states the rule — if any rung *should* buy the secret, gate it at
`trusted` instead.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

.claude/skills/world-building/references/schema.md

@@ -139,7 +139,8 @@ build failure.
 
 ## Worked example
 
-A guarded fisherman who warms up and, if trusted, names who really owns the boats.
+A guarded fisherman who warms up and names the coin — and who holds one thing no
+disposition ever buys.
 
 ```yaml
 id: person.specimen-teague
@@ -163,12 +164,26 @@ body: >
   charter is buying the wharf's silence, a little at a time.
 ```
 
+```yaml
+id: secret.specimen-drowned-clerk
+type: secret
+status: canon
+secrecy: 4
+related: [place.specimen-wharf, person.specimen-teague, fact.specimen-foreign-coin]
+body: >
+  The charter clerk who came asking after the coin went into the river in the
+  spring. Teague held his legs. He has not been out on the water since and tells
+  anyone who asks that it is his knees.
+```
+
 ```yaml
 id: npc.specimen-teague
 type: person
 status: canon
 start_disposition: cold
-related: [person.specimen-teague, fact.specimen-foreign-coin]
+related:
+  [person.specimen-teague, fact.specimen-foreign-coin,
+   secret.specimen-drowned-clerk]
 body: >
   Same man as person.specimen-teague; his interactive layer. Curt with strangers, not
   from malice but from a lifetime of watching talkers end up face-down in the
@@ -177,14 +192,22 @@ body: >
 
 knows:
   - {fact: fact.specimen-foreign-coin, gate: warm}
+  - {fact: secret.specimen-drowned-clerk, gate: never}
 
 disposition_notes: >
   Starts cold. Buying his catch, not his story, is what moves him. At warm he
-  names the coin; he never speculates aloud about who mints it.
+  names the coin; he never speculates aloud about who mints it. The clerk is the
+  one thing no rung buys — saying it aloud would hang him, and he knows it. He
+  reasons around it, steers off it, and takes it to the ground.
 ```
 
 Note: `person.specimen-teague` (secrecy 0, public) and `npc.specimen-teague` (the layer,
-persona server-only) are two entries. The fact is secrecy 2, gated at `warm`.
+persona server-only) are two entries. The chain ascends 2 → 4: the coin is gated at
+`warm` and the player earns it; the clerk is gated `never` and no disposition unlocks
+it. **That is what `never` is for.** Teague holds it — the Improviser may reason with
+it, and the player may infer it from what he *will* say — but he cannot be talked into
+saying it, because saying it would hang him. A `never` gate needs a reason like that:
+if any rung *should* buy the secret, gate it at `trusted` instead.
 
 ## Hand-authored JSON