feat(voices): canonical voice corpus + dots.tts-optimized refs

Engine-agnostic voice corpus: canonical source clip + transcript per voice,
per-engine reference sets derived by derive.py from engines.yaml profiles.
First residents donut/glados/emmie/miranda optimized + verified clean for
dots.tts (sentence-bounded ref + accurate transcript — dots leaks reference
audio into output otherwise). canonical/ + transcripts/ tracked; derived/
gitignored (regenerable). Records the dots.tts burn-in in persistent-memory.

voices/manifest.yaml

@@ -0,0 +1,35 @@
+# Canonical voice corpus registry. One row per voice; the canonical clip + its
+# full transcript are the source of truth, engine-agnostic. derive.py reads this
+# together with engines.yaml to produce per-engine reference sets.
+
+voices:
+  donut:
+    canonical: canonical/donut.wav
+    transcript: transcripts/donut.txt
+    source_sr: 44100
+    duration_s: 16.3
+    character: "sassy fairy-charm kid"
+    provenance: "cloned from the 65-frost Booth bundle (2026-08)"
+
+  glados:
+    canonical: canonical/glados.wav
+    transcript: transcripts/glados.txt
+    source_sr: 16000
+    duration_s: 25.0
+    character: "GLaDOS — flat, deliberate, menacing-cheerful"
+    provenance: "Portal GLaDOS lines"
+    warning: "LOW-SR source (16kHz) — upgrade the canonical clip if a cleaner GLaDOS source surfaces"
+
+  emmie:
+    canonical: canonical/emmie.wav
+    transcript: transcripts/emmie.txt
+    source_sr: 24000
+    duration_s: 19.3
+    provenance: "Zonos clone added 2026-07-17; origin unrecorded"
+
+  miranda:
+    canonical: canonical/miranda.wav
+    transcript: transcripts/miranda.txt
+    source_sr: 24000
+    duration_s: 16.3
+    provenance: "Zonos clone added 2026-07-17; origin unrecorded"