feat(iace): FMEA P1 — open methodology anchors + bp_iace_fmea_kb

P1 of the auto-FMEA build plan: establish the public-domain methodology
foundation (no AIAG-VDA/SAE/IEC tables reproduced).
- fmea_data_sources.go: MIL-STD-882E severity (Cat I-IV→1-10) + probability
  (A-F→1-10 with per-hour λ bands), OccurrenceFromRate(λp·α), SeverityForCategory,
  MIL-STD-1629A CriticalityCm = λp·α·β·t. Own 1-10 projection, government-anchored.
- 4 versioned source docs (MIL-STD-1629A, MIL-STD-882E, NASA RCM, FMD-91/NPRD-91)
  ingested into the new RAG collection bp_iace_fmea_kb (whitelisted).
- Tests for all scales/mappings/criticality (green).

Next (P1 step 2): fetch FMD-91/NPRD-91 bulk λ/α tables from DTIC.

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

ai-compliance-sdk/internal/iace/datasources/mil_std_1629a_fmeca.md

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+# FMECA methodology — MIL-STD-1629A (US public domain)
+
+Canonical, citable methodology source for the IACE auto-FMEA. Ingested into the
+core RAG collection `bp_iace_fmea_kb`.
+
+## Source
+- **Source:** US DoD — MIL-STD-1629A, *Procedures for Performing a Failure Mode, Effects and Criticality Analysis* (cancelled 1998, still the de-facto FMECA reference)
+- **License:** US Government work — **public domain** (17 U.S.C. §105)
+- **Attribution:** `Source: MIL-STD-1629A (US DoD), public domain`
+- **Retrieved:** 2026-06 · **Ref:** everyspec / Wikipedia FMECA
+
+## Procedure (qualitative + quantitative)
+1. Define the system, indenture levels and ground rules.
+2. For each item/function: list **failure modes** → **causes** → **local / next-higher / end effects**.
+3. Assign a **severity category** (I–IV, below).
+4. **Quantitative path (when failure-rate data exists):** compute the **modal
+   criticality** `Cm = λp · α · β · t` — λp part failure rate, α failure-mode
+   ratio (fraction of part failures in this mode), β conditional probability the
+   mode causes the analysed effect, t operating time. Item criticality `Cr = Σ Cm`.
+5. **Qualitative path (Task 101, no λ data):** assign probability-of-occurrence
+   levels A–E (Frequent → Extremely unlikely) instead of Cm.
+6. Plot items on a **severity × criticality matrix** — the open analogue of an
+   action-priority ranking (no copyrighted S×O×D RPN table needed).
+
+## Severity categories (MIL-STD-1629A / MIL-STD-882 lineage)
+| Cat | Name | Meaning |
+|---|---|---|
+| I | Catastrophic | May cause death or system loss |
+| II | Critical | Severe injury / major damage |
+| III | Marginal | Minor injury / minor damage |
+| IV | Minor (Negligible) | No injury; unscheduled maintenance/repair |
+
+## How used in IACE
+- The **Cm formula** and the **severity × criticality matrix** are the public-domain
+  criticality backbone (`CriticalityCm` in fmea_data_sources.go).
+- λp/α come from NPRD-91 / FMD-91 (public domain); β and t from the project context.
+- Severity resolves through the linked EN ISO 12100 hazard (safety-FMEA bridge).
+
+No AIAG-VDA / SAE J1739 / IEC 60812 content is reproduced.