docs(ci): establish the GravityGraph v2 Stage 0 baseline

[draedful]

Summary

Establish the repository-side Stage 0 baseline for independent Gravity Graph v1 and v2 development and release lines.

• define the v1 maintenance, v2 development, manual synchronization, cutover, rollback, and deprecation policy;
• add contributor routing and issue/pull-request templates for v1, v2, sync, release, and cutover work;
• protect the actual packed v1 contract with isolated vanilla and React 17/18 consumers, declaration validation, assets checks, and a public API baseline;
• split CI, preview, and release routing for main, future v2, and future release/v1;
• add fail-before-release branch/version/prerelease/dist-tag guards and keep post-cutover routes inactive;
• add machine-readable ruleset expectations, a GET-only verifier, offline safety tests, and an administrator runbook.

Branch and release safety

• This PR does not create v2 or release/v1.
• main remains the stable maintenance-only v1 line before cutover.
• Initial branch-creation events skip release jobs before credentials or release actions.
• The pre-cutover v2 route permits only 2.x prereleases under next; it cannot select latest.
• The future post-cutover routes remain encoded but inactive until an explicit cutover change.
• The approved future v2 creation SHA will be recorded in [Stage 0.1] Define the v1 maintenance, v2 release, synchronization, and cutover policy #315 and [Stage 0.5] Create and validate the protected v2 development branch #312 after this baseline is merged and the external ruleset gate passes.
• Repository files only describe and verify rulesets; no GitHub ruleset has been applied by this PR.

Validation

• npm run test:package-contract
  • packed @gravity-ui/graph@1.11.3;
  • 311 tarball files;
  • isolated vanilla and React 17/18 consumers;
  • TypeScript, runtime JS, CSS, declarations, exports, assets, and public API baseline.
• npm run typecheck
• npm run test
  • 31 suites passed;
  • 339 tests passed, 4 skipped, 6 todo.
• node .github/release-routing/validate.mjs check-workflows
• node .github/rulesets/verify.mjs --self-test
• git diff --check

Required external gates

Before creating v2:

1. assign the repository administrator and record the bypass decision in [Stage 0.4] Prepare and verify rulesets for main and v2 #317, starting with no bypass;
2. activate and verify rulesets for main and the future v2 ref;
3. merge this baseline after all required checks pass;
4. record the exact resulting main SHA in [Stage 0.1] Define the v1 maintenance, v2 release, synchronization, and cutover policy #315 and [Stage 0.5] Create and validate the protected v2 development branch #312;
5. create v2 from that exact SHA and immediately verify effective protection.

Related: #310, #312, #313, #314, #315, #316, #317.

Summary by Sourcery

Establish a Stage 0 baseline for parallel v1 maintenance and v2 development by formalizing branch/release policy, strengthening CI and release safety checks, and protecting the published v1 package contract.

Enhancements:

• Extend CI and E2E workflows to run on both main and v2 branches and introduce a dedicated package contract job that validates release routing and the published artifact.
• Split the previous unified release workflow into separate guarded workflows for v1 and v2 with explicit branch, version, prerelease, and dist-tag validation and distinct preview routing.
• Add an automated validator for release-routing configuration and an offline ruleset verifier to enforce expected protection and required checks.
• Enhance the build pipeline to normalize declaration files and enforce a stable public API baseline for the v1 package contract.

CI:

• Add contributor-facing issue and pull-request templates to capture v1/v2 routing intent, synchronization records, and release/cutover evidence.

Documentation:

• Document the v1/v2 branch, release, synchronization, and cutover policy, contributor routing rules, and ruleset administration/runbooks, and link them from the main README and CONTRIBUTING guide.

Tests:

• Introduce a package-contract test suite that builds and packs the library, validates exports, declarations, assets, and public API, and exercises vanilla and React 17/18 consumers to guard the v1 npm contract.

[gravity-ui-bot]

Preview is ready.