feat(iace): ESAW accident-stats RAG pipeline + real 2023 risk anchors

Executes the accident-statistics pipeline for the risk anchors:
- Refresh contactModeEvidence with real Eurostat ESAW figures
  (dataset hsw_ph3_08, reference year 2023): impact 24.0%/21.4%,
  struck-by 13.0%/23.8%, sharp 14.5%, trapped/crushed 13.8% (fatal),
  + new physical/mental-stress mode 24.7% → ergonomic. GT-calibrated
  tier VALUES unchanged; the real data confirms the ordering.
- Add the versioned source document (datasources/esaw_accident_stats_2023.md,
  ESAW CC BY 4.0 + OSHA public-domain context) that is ingested into the
  core RAG collection bp_iace_accident_stats for searchable evidence.
- Whitelist bp_iace_accident_stats in the RAG search handler so seeding
  can full-text search the statistics with citation at seed time.

Two-layer design: the small license-tagged code table stays the deterministic
tier/citation lookup; the RAG holds the searchable source evidence.

Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>

ai-compliance-sdk/internal/iace/DATA_SOURCES.md

@@ -27,9 +27,16 @@ do **not** reproduce any standard's risk-graph table, decision tree or matrix.
   any generated risk-assessment export that shows engine risk numbers.
 - **URL:** https://ec.europa.eu/eurostat/statistics-explained/index.php/Accidents_at_work_-_statistics_on_causes_and_circumstances
 - **Aggregate facts used (anchor only):** contact-mode shares of accidents at
-  work, e.g. impact with stationary object ~24%, struck by moving object ~13%
-  (non-fatal) / ~24% (fatal), trapped/crushed ~14% (fatal), contact with sharp
-  agent ~15%. Retrieved 2026-06.
+  work. **Dataset `hsw_ph3_08`, reference year 2023** (Figure 7, "contact —
+  mode of injury"), EU shares:
+  - Physical/mental stress: 24.7% (non-fatal)
+  - Impact with stationary object (victim in motion): 24.0% (non-fatal) / 21.4% (fatal)
+  - Contact with sharp/pointed/rough agent: 14.5% (non-fatal)
+  - Struck by object in motion / collision: 13.0% (non-fatal) / 23.8% (fatal)
+  - Trapped / crushed: 13.8% (fatal)
+
+  Retrieved 2026-06. The source document is also ingested into the core RAG
+  collection `bp_iace_accident_stats` for searchable evidence at seeding time.
 
 ## Acceptable supplements