Add Dockerfile for Leptos Chat deployment

crates/leptos-chat/.dockerignore

@@ -0,0 +1,7 @@
+*
+!src/
+!style/
+!Cargo.toml/
+!index.html
+!Trunk.toml
+

crates/leptos-chat/Dockerfile

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+# Build stage
+FROM rust:1-alpine AS builder
+
+# Install build dependencies
+RUN apk add --no-cache npm nodejs musl-dev pkgconfig openssl-dev git curl bash
+
+RUN curl -L --proto '=https' --tlsv1.2 -sSf https://raw.githubusercontent.com/cargo-bins/cargo-binstall/main/install-from-binstall-release.sh | bash
+
+WORKDIR /app
+
+# Copy manifest first (cache deps)
+COPY . .
+# Install trunk
+RUN cargo install wasm-bindgen-cli
+
+RUN cargo binstall trunk
+
+# Build release artifacts
+RUN rustup target add wasm32-unknown-unknown && export RUSTFLAGS='--cfg getrandom_backend="wasm_js"' && trunk build --release
+
+# Final stage: static web server
+FROM caddy:2-alpine
+
+# Copy built assets into Caddy's web root
+COPY --from=builder /app/dist /usr/share/caddy
+
+EXPOSE 8788
+CMD ["caddy", "file-server", "--root", "/usr/share/caddy", "--listen", ":8788"]