Release/0.1.9

[Lythaeon]

Summary

• Prepared the 0.1.9 release branch by bumping crate version and finalizing the changelog.
• Included Phase 0 architecture guardrails/docs reorganization work and CI enforcement.
• Removed the flaky gRPC runtime transport test that was causing CI instability.

Changes

• Bumped version to 0.1.9 in Cargo.toml and Cargo.lock.
• Added ## 0.1.9 release section in CHANGELOG.md (Released: 2026-02-13).
• Added architecture guardrail tooling and CI integration:
  • scripts/check_architecture.sh
  • cargo make architecture-check
  • workflow updates in PR/release CI
• Reorganized docs into typed structure:
  • docs/guides, docs/assets, docs/architecture/{ard,adr,srs,rfc,patterns}
  • updated internal references and docs index files
• Removed flaky test:
  • protocol::runtime::tests::transport_http_grpc::grpc_protocols_emit_success_metric
  • removed now-unused gRPC mock test helpers
• Made architecture check portable by adding find/grep fallback when rg is unavailable.

Checks

• cargo make format
• cargo make clippy
• cargo make test
• cargo make architecture-check
• cargo make test-wasm (not run; no WASM changes)
• cargo make audit (not run; no dependency changes)
• cargo make deny (not run; no dependency changes)
• cargo publish --dry-run --locked (attempted but blocked in this environment by crates.io DNS resolution)