fix(docker): rewrite Dockerfile for standalone build with Alpine

- Use Alpine Linux instead of Debian for smaller image size
- Build as standalone using published solverforge crate from crates.io
- Remove dependency on local solverforge-rs workspace
- Build with musl target for static linking
- Build context is now just rust/employee-scheduling/ (works with CI)

Author: blackopsrepl

rust/employee-scheduling/Dockerfile

@@ -1,45 +1,39 @@
 # Multi-stage build for SolverForge Employee Scheduling (Rust)
 #
-# Build context should be the parent directory containing both:
-#   - solverforge-rs/
-#   - solverforge-quickstarts/
-#
-# Example:
-#   docker build -f solverforge-quickstarts/rust/employee-scheduling/Dockerfile \
-#                -t employee-scheduling-rust .
-
-FROM rust:1.83-bookworm AS builder
+# Build context: rust/employee-scheduling/
+# Uses published solverforge crate from crates.io
 
-WORKDIR /build
+FROM rust:1.83-alpine AS builder
 
-# Copy solverforge-rs workspace (local dependency)
-COPY solverforge-rs/ ./solverforge-rs/
+# Install build dependencies
+RUN apk add --no-cache musl-dev
 
-# Copy quickstarts
-COPY solverforge-quickstarts/rust/employee-scheduling/ ./solverforge-quickstarts/rust/employee-scheduling/
+WORKDIR /build
 
-WORKDIR /build/solverforge-quickstarts/rust/employee-scheduling
+# Copy workspace files
+COPY Cargo.toml Cargo.lock ./
+COPY src/ ./src/
+COPY static/ ./static/
+COPY solver.toml ./
 
-# Build release binary
-RUN cargo build --release
+# Build release binary with musl target for static linking
+RUN cargo build --release --target x86_64-unknown-linux-musl
 
-# Runtime stage - minimal image
-FROM debian:bookworm-slim
+# Runtime stage - minimal Alpine image
+FROM alpine:latest
 
-RUN apt-get update && \
-    apt-get install -y --no-install-recommends ca-certificates && \
-    rm -rf /var/lib/apt/lists/*
+RUN apk add --no-cache ca-certificates
 
 WORKDIR /app
 
-# Copy binary from builder
-COPY --from=builder /build/solverforge-quickstarts/rust/employee-scheduling/target/release/employee-scheduling ./employee-scheduling
+# Copy binary from builder (musl static binary)
+COPY --from=builder /build/target/x86_64-unknown-linux-musl/release/employee-scheduling ./employee-scheduling
 
 # Copy static files
-COPY --from=builder /build/solverforge-quickstarts/rust/employee-scheduling/static/ ./static/
+COPY --from=builder /build/static/ ./static/
 
 # Copy solver config
-COPY --from=builder /build/solverforge-quickstarts/rust/employee-scheduling/solver.toml ./solver.toml
+COPY --from=builder /build/solver.toml ./solver.toml
 
 # Expose port 7860 (HF Spaces default)
 EXPOSE 7860