Align artifacts with canonical URT v5.1 specification

Fixes inconsistencies discovered during audit against urt-taxonomy/:

- urt_profile ENUM: Add 'lite' and 'core' profiles (was missing)
- USN format: Use canonical regex from spec (was non-compliant)
- USN valence encoding: Add V0 (0) and V± (±) support
- USN grammar: Add Lite (URT:L:) and Core (URT:C:) formats
- Dimension codes: Fix temporal (TC/TR/TH/TF), evidence (ES/EI/EC),
  comparative (CR-N/CR-B/CR-W/CR-S) in decisions doc
- LLM contract: Full USN regex validation pattern

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

.artifacts/ReviewIQ-v32-Decisions.md

@@ -76,15 +76,15 @@ Based on: v3.1.2 (commit f998277)
 - `urt_actionability` — A1, A2, A3
 
 **Context & Evidence:**
-- `urt_temporal` — T1, T2, T3
-- `urt_evidence` — E1, E2, E3
-- `urt_comparative` — CR1, CR2, CR3
+- `urt_temporal` — TC (current), TR (recent), TH (historical), TF (future)
+- `urt_evidence` — ES (stated), EI (inferred), EC (contextual)
+- `urt_comparative` — CR-N (none), CR-B (better), CR-W (worse), CR-S (same)
 
 **Classification:**
-- `urt_profile` — factual, emotional, comparative, etc.
+- `urt_profile` — lite, core, standard, full
 - `urt_confidence` — low, medium, high
-- `urt_relation` — elaborates, contrasts, causes, etc.
-- `urt_entity_type` — person, product, location, etc.
+- `urt_relation` — cause_of, effect_of, contrast, resolution
+- `urt_entity_type` — location, staff, product, process, time, other
 
 ---