Rename repository identity to contextforge-data-plane

[lucarlig]

Summary

• rename the Cargo workspace crates, binary, Rust imports, application state, and lockfile entries from contextforge-gateway-rs to contextforge-data-plane
• align CLI environment variables, logging and telemetry identities, Docker images, Compose resources, Nginx internals, GitHub metadata, diagrams, and book content with the new name
• use distinct network identities: contextforge-stack-net for the shared control-plane/data-plane integration stack and contextforge-data-plane-net for lightweight local data-plane development
• add inherited repository, homepage, and readme metadata to every renamed Cargo package
• restore detailed local-development and CPEX demo documentation using server/discover, per-request metadata, and MCP 2026-07-28
• retain explicitly documented compatibility names where they are external contracts: the ContextForgeGatewayRuntimePluginConfig Redis key, the /contextforge-rs route, and the independently hosted cpex-plugins-rs repository

Scope

This PR does not migrate, replace, remove, or otherwise change the implementation of the mcp_counter and mcp_conformance fixtures. Their Dockerfiles differ from main only in the OCI repository-source label. The local Compose fixture configuration retains its existing behavior and changes only the Compose project and network identities.

The previously proposed official Rust SDK source migration and generated SDK lockfile have been removed from this PR. Any fixture lifecycle or dependency change belongs in a separate change.

Why

The GitHub repository moved to contextforge-org/contextforge-data-plane, but its package and operational identities still used the former repository name. This left Cargo, deployment configuration, observability metadata, and documentation inconsistent with the canonical repository.

The full Compose environment contains both the ContextForge control plane and data plane, while the lightweight Compose environment supports host-side data-plane development. Their network names now reflect those distinct scopes.

Impact

The primary binary is now contextforge-data-plane, internal crates use the contextforge-data-plane-* names, and runtime configuration uses the CONTEXTFORGE_DATA_PLANE_* environment-variable prefix. Docker and documentation consumers must use the renamed identities.

No MCP fixture implementation or SDK dependency changes are included.

Validation

• all Make targets: make help, make docker-prod, make testing-up, and make testing-down
• clean production Docker build and contextforge-data-plane:latest --help smoke test
• docker/dev.Dockerfile build and CLI smoke test
• base testing stack health checks for the data plane, control plane, Redis, PostgreSQL, PgBouncer, and Fast Time
• base, local, Langfuse, and OpenTelemetry/Prometheus Compose combinations with docker compose config --quiet
• rendered Compose topology assertions for the shared and local network identities
• actionlint
• cargo shear --check-test-targets --deny-warnings --locked
• full pre-commit suite: Cargo fmt, Clippy, deny, Nextest, build, and benchmark compilation
• cargo test --workspace --all-targets --all-features --locked (89 passed, 2 ignored)
• mdbook build docs/book
• mdbook test docs/book
• Cargo metadata assertion for all renamed packages
• final diff audit confirming fixture Dockerfiles contain only OCI source-label changes, local fixture behavior matches main, and no SDK lockfile remains

[Lang-Akshay]

Thanks for the much needed PR @lucarlig

LGTM

[gandhipratik203]

The renaming looks consistent. LGTM!