feat(iace): ISO 12100 Anhang B mapping — split noise/vibration + section identifier

Phase 16 of the Klaerungen / risk-assessment polish. Sources from
EN ISO 12100 Anhang B Tabelle B.1 are now first-class:

A) HazardPattern.ISO12100Section identifier (string), persisted only as
   the section number (e.g. "6.3.5.5") — not the norm text. Keeps the
   library urheberrechtlich neutral (DIN/Beuth license). 57 patterns
   labeled today; rest will follow on touch.

B) Category split per ISO 12100 Nr. 4 vs Nr. 5:
   - 16 patterns reclassified noise_vibration -> noise_hazard
   - 7  patterns reclassified noise_vibration -> vibration_hazard
   - 1  pattern (HP228 UV-/Laermexposition) kept multi-cat
   acceptableMeasureCategories now accepts both new aliases plus the
   legacy noise_vibration. Coverage test recognises both as valid.

C) 5 new ISO-12100-Annex-B gap patterns (HP1900-HP1904):
   - HP1900 Vakuum-Verletzung (6.3.5.5)
   - HP1901 Federenergie / elastische Elemente (6.2.10)
   - HP1902 Rutschen/Stolpern auf rauer Oberflaeche (6.3.5.6)
   - HP1903 Hochdruckinjektion (6.3.5.4) — includes clarifying
            "no hand-locating of leaks" question
   - HP1904 Ersticken durch Brustkorbquetschung (6.3.5.2)

The library now mirrors the ISO 12100 Annex B structure for the gaps
the Bremse benchmark surfaced.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

ai-compliance-sdk/internal/iace/pattern_engine.go

@@ -69,6 +69,7 @@ type PatternMatch struct {
 	ApplicableLifecycles []string `json:"applicable_lifecycles,omitempty"`
 	SuggestedMeasureIDs      []string `json:"suggested_measure_ids,omitempty"`
 	ClarificationQuestionsDE []string `json:"clarification_questions_de,omitempty"`
+	ISO12100Section          string   `json:"iso_12100_section,omitempty"`
 }
 
 // HazardSuggestion is a suggested hazard from pattern matching.
@@ -224,6 +225,7 @@ func (e *PatternEngine) Match(input MatchInput) *MatchOutput {
 			ApplicableLifecycles: p.ApplicableLifecycles,
 			SuggestedMeasureIDs:      p.SuggestedMeasureIDs,
 			ClarificationQuestionsDE: p.ClarificationQuestionsDE,
+			ISO12100Section:          p.ISO12100Section,
 		})
 
 		for _, cat := range p.GeneratedHazardCats {