Automate generated reference doc source updates

[danielporterda]

Summary

Adds version-driven automation for generated reference docs:

• adds a source updater that discovers upstream versions, rewrites checked-in source config pins, emits a JSON summary, and exports GitHub Actions outputs
• adds a daily/manual GitHub Action that updates pins, regenerates docs only when pins changed, validates, uploads artifacts, and opens/updates a PR
• makes generated-reference source configs the durable lock state by adding explicit pins for protobuf, gRPC, Wallet OpenRPC, and Splice OpenAPI
• updates previously auto-discovering generators to honor committed versions pins by default
• passes GITHUB_TOKEN/GH_TOKEN through Splice OpenAPI GitHub API reads to avoid unauthenticated CI rate limits

Validation

Passed:

direnv exec /Users/danielporter/control/.worktrees/docs-reference-doc-source-updater python3 -m pytest tests/test_update_reference_doc_sources.py tests/test_splice_mintlify_openapi.py tests/test_canton_protobuf_generator.py tests/test_wallet_kernel_nav.py tests/test_typescript_bindings_reference.py

direnv exec /Users/danielporter/control/.worktrees/docs-reference-doc-source-updater npm run generate:all-reference-docs -- --dry-run

git diff --check

Known existing issues observed while validating:

• python3 -m pytest tests currently has unrelated characterization/golden failures on this branch.
• A full local regeneration attempt was blocked by GitHub API rate limiting in the existing Splice OpenAPI release lookup; this PR patches that helper to use the workflow token in CI.