fix: eprintln for Docker logs, include migrations in stub build

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

infra/colony/Dockerfile

@@ -11,15 +11,16 @@ FROM rust:1.86-slim AS backend
 RUN apt-get update && apt-get install -y pkg-config libssl-dev && rm -rf /var/lib/apt/lists/*
 WORKDIR /app
 
-# Cache dependency build: copy manifests first, create stub sources, build deps
+# Cache dependency build: copy manifests + migrations, create stub sources
 COPY Cargo.toml Cargo.lock ./
 COPY crates/colony-types/Cargo.toml crates/colony-types/Cargo.toml
 COPY crates/colony/Cargo.toml crates/colony/Cargo.toml
+COPY crates/colony/migrations crates/colony/migrations
 RUN mkdir -p crates/colony-types/src crates/colony/src \
     && echo "fn main() {}" > crates/colony/src/main.rs \
     && echo "" > crates/colony-types/src/lib.rs \
     && cargo build --release -p colony 2>/dev/null || true \
-    && rm -rf crates/
+    && rm crates/colony/src/main.rs crates/colony-types/src/lib.rs
 
 # Now copy real source and build (deps already cached)
 COPY crates/ crates/