v0.13.0:4 - redaction gateway, embeddings proxy, expanded audio API

- Add redaction gateway (redaction_gateway.py, redaction/ scrub + tests)
- Add embeddings proxy and spark_embed service (Dockerfile + main.py)
- Expand audio_proxy with speaker-aware handling; deep_health/health/server updates
- Package: configureSparks action + sparkConfig model updates, manifest/main wiring
- Docs: AUDIO_API, EMBEDDINGS, REDACTION_GATEWAY; HANDOFF and runbook/known-issues refresh

image/app/redaction/__init__.py

@@ -0,0 +1,17 @@
+"""Redaction engine — VENDORED from the CRM repo for behavioral parity.
+
+`scrub.py` and `test_scrub_leak.py` in this directory are byte-for-byte copies of
+the CRM's reference implementation, kept verbatim so re-syncing is a trivial `cp`
+and a diff. Do NOT edit scrub.py here — change it in the CRM repo, re-vendor, and
+re-run the leak test. The Spark Control *gateway* (server-held pseudonym map, TTL,
+map_handle, local-Qwen NER backstop, the /scrub + /rehydrate HTTP contract) is
+built AROUND this engine in app/redaction_gateway.py — the engine's detection
+logic is never reimplemented.
+
+Parity source: CRM backend/redaction/scrub.py
+  sha256: 412c5fdf7006275a98fa427457293a43256165e97eebaee878c310c68cea054b
+  (re-vendored after the upstream hardening pass: currency-only amounts with a
+   word-boundary suffix, SWIFT/letter-prefixed-account Tier-1, NFKC+zero-width
+   normalization, single-pass rehydrate, and the dictionary deleted_at fix.)
+Acceptance: backend/redaction/test_scrub_leak.py — must pass against this copy.
+"""