chore(api): bundle canon log schemas into image; repo-root build context

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

api/Dockerfile

@@ -1,8 +1,7 @@
-# /api — FastAPI proxy (charter §4). Docker-based for parity across
-# dev / homelab VPS / fly.io.
+# /api — FastAPI proxy (charter §4). Build context is the repo root so the
+# canon log schemas (/docs/schemas) are bundled into the image.
 FROM python:3.12-slim
 
-# Faster, quieter Python in containers.
 ENV PYTHONUNBUFFERED=1 \
     PYTHONDONTWRITEBYTECODE=1 \
     PIP_NO_CACHE_DIR=1
@@ -10,11 +9,12 @@ ENV PYTHONUNBUFFERED=1 \
 WORKDIR /app
 
 # Install deps first so the layer caches when only app code changes.
-COPY requirements.txt .
+COPY api/requirements.txt .
 RUN pip install --no-cache-dir -r requirements.txt
 
-# App code.
-COPY app ./app
+# App code + the schema contract (single source of truth in docs/schemas).
+COPY api/app ./app
+COPY docs/schemas ./schemas
 
 # Run as non-root.
 RUN useradd --create-home --uid 1000 appuser