feat: add Dockerfile, .dockerignore, and README; remove common crate

Co-authored-by: Copilot <copilot@github.com>

Dockerfile

@@ -0,0 +1,57 @@
+# ----- build -----
+FROM rust:slim-bookworm AS builder
+
+RUN apt-get update && apt-get install -y --no-install-recommends sqlite3 && rm -rf /var/lib/apt/lists/*
+
+WORKDIR /build
+
+# Cache dependency compilation separately from source
+COPY Cargo.toml Cargo.lock ./
+COPY crates/adapters/auth/Cargo.toml              crates/adapters/auth/Cargo.toml
+COPY crates/adapters/event-publisher/Cargo.toml   crates/adapters/event-publisher/Cargo.toml
+COPY crates/adapters/metadata/Cargo.toml          crates/adapters/metadata/Cargo.toml
+COPY crates/adapters/poster-fetcher/Cargo.toml    crates/adapters/poster-fetcher/Cargo.toml
+COPY crates/adapters/poster-storage/Cargo.toml    crates/adapters/poster-storage/Cargo.toml
+COPY crates/adapters/rss/Cargo.toml               crates/adapters/rss/Cargo.toml
+COPY crates/adapters/sqlite/Cargo.toml            crates/adapters/sqlite/Cargo.toml
+COPY crates/adapters/template-askama/Cargo.toml   crates/adapters/template-askama/Cargo.toml
+COPY crates/application/Cargo.toml                crates/application/Cargo.toml
+COPY crates/domain/Cargo.toml                     crates/domain/Cargo.toml
+COPY crates/presentation/Cargo.toml               crates/presentation/Cargo.toml
+
+# Stub every crate so cargo can resolve and fetch deps
+RUN find crates -name "Cargo.toml" | sed 's|/Cargo.toml||' | \
+    xargs -I{} sh -c 'mkdir -p {}/src && echo "fn main(){}" > {}/src/main.rs && echo "" > {}/src/lib.rs'
+
+RUN cargo fetch
+
+# Now copy real sources (invalidates cache only on source changes)
+COPY crates ./crates
+
+# sqlx macros verify queries at compile time; create a real DB from migrations
+RUN sqlite3 /build/dev.db \
+      < crates/adapters/sqlite/migrations/0001_initial.sql && \
+    sqlite3 /build/dev.db \
+      < crates/adapters/sqlite/migrations/0002_users.sql
+
+ENV DATABASE_URL=sqlite:///build/dev.db
+
+RUN cargo build --release -p presentation
+
+# ----- runtime -----
+FROM debian:bookworm-slim
+
+RUN apt-get update && apt-get install -y --no-install-recommends \
+    ca-certificates \
+ && rm -rf /var/lib/apt/lists/*
+
+WORKDIR /app
+
+COPY --from=builder /build/target/release/presentation ./presentation
+COPY static ./static
+
+EXPOSE 3000
+
+ENV RUST_LOG=presentation=info,tower_http=info
+
+CMD ["./presentation"]