Add V1 infrastructure: Gitea Actions CI/CD + Fly.io + Cloudflare Pages

- Gitea Actions workflows: ci.yml (tests+clippy+fmt), benchmark.yml (P99 gate), deploy.yml (Fly+CF)
- Fly.io configs: proxy (shared-cpu, 256MB, min 1 machine), API (scale-to-zero)
- Dockerfiles: multi-stage Rust builds for proxy and API binaries
- INFRASTRUCTURE.md: full V1 stack (~$5/mo), AWS migration path, Gitea runner setup, DNS plan
- Stack: Fly.io + Cloudflare Pages + Neon + Upstash + Gitea Actions

products/01-llm-cost-router/Dockerfile.api

@@ -0,0 +1,13 @@
+# --- Build stage ---
+FROM rust:1.78-slim AS builder
+WORKDIR /app
+COPY Cargo.toml Cargo.lock ./
+COPY src/ src/
+RUN cargo build --release --bin dd0c-api
+
+# --- Runtime stage ---
+FROM debian:bookworm-slim
+RUN apt-get update && apt-get install -y ca-certificates && rm -rf /var/lib/apt/lists/*
+COPY --from=builder /app/target/release/dd0c-api /usr/local/bin/
+EXPOSE 3000
+CMD ["dd0c-api"]