v0.24.0: strengthen routing policy and E2E delivery gates

[wutongci]

Summary

• align routing-policy execution and simulation across model/protocol admission, pricing, failover, capacity, and exclusion evidence
• restore and cover the enterprise plugin center, gateway protocols, identity, pricing, exports, maintenance, and recovery journeys
• establish machine-readable E2E capability/scenario evidence and enforce it in PR, nightly, and release workflows
• harden isolated release fixtures for S3 URL encoding, browser response ordering, and cross-platform PostgreSQL lifecycle startup
• update product metadata and changelog to 0.24.0

Verification

• bash scripts/test.sh backend-checks
• npm run typecheck
• npm run test:unit (40 files, 148 tests)
• npm run build
• npm run check:e2e-coverage (43 routes, 49 scenarios)
• npm run check:e2e-completeness (192 operations, zero required evidence gaps)
• npm run check:public-doc-links
• npm run check:enterprise-surface
• npm run check:workflow-pipefail
• npm run check:release-browser-contract
• local PR browser gate: 61 passed, 47 registry-controlled skips, zero failures
• bash scripts/test-system-update-lifecycle.sh: upgrade, restart, rollback, restart passed against a dedicated PostgreSQL instance
• node --test scripts/fake-s3.test.mjs: 7 passed
• go test ./internal/system -count=1
• git diff --check and shell syntax checks

Release boundary

GitHub CI and the tag release workflow are authoritative for PostgreSQL 16, container smoke, Linux release artifacts, installer acceptance, upgrade/rollback, and production browser journeys. Production deployment will use only the published GitHub Release Linux amd64 artifact after those gates pass. The production PostgreSQL database will be backed up and preserved; no database reset is authorized or planned.