feat(simulation): contraband detection + dialogue confidence gate (D-075) (#425, #524)

Contraband detection (Task #425, D-065):
- New module: simulation/contraband.rs — NPC scan checks carried items
  against the KnowledgeGraph confidence gate. NPCs with Authority access
  can initiate a scan; scan outcome depends on item CarriedBy + KG entry.
- Adds ContrabandScanResult event type and ContrabanEntry component.
- Wired into simulation/mod.rs module list.

Dialogue confidence gate (Task #524, D-075 — OQ-18 resolution):
- relationship_to_trust() gains confidence parameter (KnowledgeConfidence).
- Trust tier mapping: (Friendly, KnowsDetails+)→Secret, (Friendly|Known,
  KnowsOf+)→Real, otherwise Surface. Access tier (Layer 1) unchanged.
- Caller process_talk_interaction passes observer KG confidence_of target.
- Resolves OQ-18: confidence co-gates TrustTier, not AccessTier.

Supporting changes:
- decisions/content.md: add D-075 (16 decisions, dated 2026-02-19)
- knowledge/types.rs: expose KnowledgeConfidence comparison helpers
- knowledge/registry.rs: minor API polish
- bridge/types.rs: ContrabandScanResult wire type
- bridge/text_renderer.rs: render contraband scan status
- perception/observer: include carried item count in snapshot
- npc/mod.rs: NPC scan range constant, authority flag

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

decisions/content.md

@@ -159,6 +159,27 @@ How narrative, NPCs, and world content are created: content tiers, NPC generatio
 - **Raised by:** Inigo (insert-tech/organic split), Paula (cognitive architecture framing and trust model connection)
 - **Dissent:** None
 
+### D-075: Dialogue filtering — layered confidence gate on trust tier (OQ-18 resolution)
+- **Date:** 2026-02-19
+- **Decision:** KnowledgeConfidence ([D-041](architecture.md#d-041-knowledge-graph-data-model)) acts as a co-gate on TrustTier ([D-028](#d-028-dialogue-architecture--tagged-line-pools-with-four-relational-layers) Layer 3), not on AccessTier (Layer 1). Access tier and trust tier remain two separate filtering dimensions with different drivers:
+  1. **AccessTier (Layer 1):** Gated by `RelationshipState` only. Social position determines what *categories* of dialogue are available. No change from current implementation. Character archetype effects are emergent — the detective's investigation naturally creates PersonOfInterest relationships (Authority access), the smuggler's social arc naturally creates Known/Friendly relationships (Peer/Insider access). No archetype tag on the pipeline.
+  2. **TrustTier (Layer 3):** Gated by both `RelationshipState` AND `KnowledgeConfidence`:
+     - **Surface:** any relationship + any confidence — baseline, always available.
+     - **Real:** (Friendly or Known) + KnowsOf+ — requires both rapport and substantive knowledge.
+     - **Secret:** Friendly + KnowsDetails+ — requires both deep rapport and actionable knowledge.
+  3. **KnowledgeConfidence does NOT gate AccessTier.** Access is a social/positional concept ("who are you to me?"), not an information concept ("what do you know about me?"). A stranger can have Authority access (detective flashes badge) with zero knowledge. An insider can have Peer access before they know anything specific about the target.
+- **Key design choice — no archetype dimension.** The dialogue pipeline does not add a character-archetype tag (detective/smuggler) as a filtering axis. Instead, archetype effects on dialogue emerge from: (a) different starting RelationshipStates driven by gameplay (detective institutions → Authority access, smuggler social network → Insider access), (b) different knowledge accumulation rates (detective's analytical lattice gains KnowsOf faster → Real trust earlier), (c) D-028 Layer 1 access tags on lines already encode "this line is for authority figures" vs "this line is for insiders." This is architecturally consistent with D-010 principle 3 (no baking player identity into the game loop).
+- **Rationale:** Three reasons for layered-but-not-archetype:
+  1. *Separation of concerns.* Access (social position) and trust (relationship depth x knowledge depth) answer different questions. Collapsing them into one axis would require rewriting D-028's four-layer model and D-035's tag taxonomy — both confirmed and implemented.
+  2. *Minimal code change.* The only implementation change is adding a `KnowledgeConfidence` parameter to `relationship_to_trust()` in `server/src/simulation/dialogue.rs`. The caller already has access to the observer's KnowledgeGraph. No new components, no new tags, no content format changes.
+  3. *Emergent archetype distinction.* Hardcoding archetype tags creates a maintenance burden (new character = new tag = new content variant) and reduces the "two keyholes on the same world" experience. When the detective and smuggler experience different dialogue from the same NPC, it should be because they have different *relationships* and *knowledge*, not because a tag excluded them.
+- **Implementation change to #305:** `relationship_to_trust()` gains a `confidence` parameter. Mapping: `(Friendly, KnowsDetails+) → Secret`, `(Friendly|Known, KnowsOf+) → Real`, `(_ , _) → Surface`. Caller in `process_talk_interaction` passes `observer_kg.confidence_of(&target_sid)` to the updated function.
+- **Resolves:** OQ-18
+- **Amends:** [D-041](architecture.md#d-041-knowledge-graph-data-model) (confirms confidence-to-trust mapping; supersedes the preliminary 1:1 sketch in D-041 "Key design choices" bullet 3 with the layered model above), [D-028](#d-028-dialogue-architecture--tagged-line-pools-with-four-relational-layers) (Layer 3 trust now requires both relationship AND confidence)
+- **Cross-reference:** [D-028](#d-028-dialogue-architecture--tagged-line-pools-with-four-relational-layers), [D-035](#d-035-converged-tag-taxonomy-for-dialogue-and-monologue-line-pools), [D-041](architecture.md#d-041-knowledge-graph-data-model), [D-062](#d-062-invisible-locked-dialogue-options) (confidence progression naturally unlocks new trust tiers, creating the "new options appearing" reward)
+- **Raised by:** Tyre (technical analysis, architecture synthesis)
+- **Dissent:** Pending review. Sprint briefing flags Gestalt and Nigel for archetype dimension input.
+
 ---
 
-*15 decisions. Last updated: 2026-02-16*
+*16 decisions. Last updated: 2026-02-19*