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>

content/lore/specimen.md

@@ -1,11 +1,12 @@
 # SPECIMEN — format example, NOT game canon
 
-> A synthetic disposition-gate specimen: the shape a guarded-then-warm NPC and a
-> single earned personal reveal take in the bible. Authored `status: candidate`,
-> so the build VALIDATES it (`--check` resolves its gate against the ladder) but
-> emits NOTHING to `content/world` or `content/server`. This is a teaching
-> example for the world-building skill, not part of the Margreave. Do not wire
-> real content to these ids.
+> A synthetic disposition-gate specimen: the shape a guarded-then-warm NPC takes
+> in the bible, with an ascending knowledge chain — one reveal the player earns at
+> `warm`, and a `never`-gated core the NPC knows and no disposition ever unlocks.
+> Authored `status: candidate`, so the build VALIDATES it (`--check` resolves its
+> gates against the ladder) but emits NOTHING to `content/world` or
+> `content/server`. This is a teaching example for the world-building skill, not
+> part of the Margreave. Do not wire real content to these ids.
 
 ```yaml
 id: place.specimen-wharf
@@ -40,13 +41,27 @@ body: >
   wharf's silence, a little at a time.
 ```
 
+```yaml
+id: secret.specimen-drowned-clerk
+type: secret
+status: candidate
+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: candidate
 secrecy: 0
 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
@@ -55,8 +70,11 @@ 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.
 ```