Implement multi-platform build system with pure Go support

- Introduced a comprehensive build system that supports multiple platforms (Linux, macOS, Windows, Android) using pure Go builds (`CGO_ENABLED=0`).
- Updated all build and test scripts to ensure compatibility with the new purego approach, allowing for dynamic loading of `libsecp256k1` at runtime.
- Added detailed documentation on the build process, platform detection, and deployment options.
- Enhanced CI/CD workflows to automate builds for all supported platforms and include necessary libraries in releases.
- Updated `.gitignore` to exclude build output files.
- Created new documentation files for deployment and multi-platform build summaries.

cmd/benchmark/Dockerfile.next-orly

@@ -48,6 +48,11 @@ COPY . .
 # Build the relay
 RUN CGO_ENABLED=1 GOOS=linux go build -gcflags "all=-N -l" -o relay .
 
+# Copy libsecp256k1.so if it exists in the repo
+RUN if [ -f pkg/crypto/p8k/libsecp256k1.so ]; then \
+        cp pkg/crypto/p8k/libsecp256k1.so /build/; \
+    fi
+
 # Create non-root user (uid 1000) for runtime in builder stage (used by analyzer)
 RUN useradd -u 1000 -m -s /bin/bash appuser && \
     chown -R 1000:1000 /build
@@ -66,6 +71,9 @@ WORKDIR /app
 # Copy binary from builder
 COPY --from=builder /build/relay /app/relay
 
+# Copy libsecp256k1.so if it was built with the binary
+COPY --from=builder /build/libsecp256k1.so /app/libsecp256k1.so 2>/dev/null || true
+
 # Create runtime user and writable directories
 RUN useradd -u 1000 -m -s /bin/bash appuser && \
     mkdir -p /data /profiles /app && \