chore(ci): reduce redundant validation work

[kubohiroya]

Closes #1562

Scope

• Classify pnpm-lock.yaml only and workspace+lockfile changes as affected validation instead of full validation.
• Split repository-wide checks so affected PRs keep blocking dependency/policy checks while full validation keeps the heavier license summary.
• Replace Naming Audit base worktree generation with fixed baseline comparison via scripts/naming-audit-baseline.json.
• Fail Naming Audit when fixed baseline errors are resolved without updating the baseline, preventing stale baseline drift.
• Update CI and naming audit specs.

Rollback

• Revert .github/workflows/ci-validation.yml, .github/workflows/naming-audit.yml, the related CI/naming audit scripts, docs, package scripts, and scripts/naming-audit-baseline.json.

Verification

• pnpm exec prettier --check ...
• pnpm vitest run --config scripts/vitest.config.ts scripts/__tests__/namingAuditCiUtils.unit.test.ts scripts/__tests__/requiresNamingAuditFullScan.test.ts
• pnpm run ci:validation:test
• pnpm tsx scripts/naming-audit.ts --ci --changed-since HEAD --baseline scripts/naming-audit-baseline.json
• pnpm run ci:checks:affected

Note: actionlint is not installed in this workspace, so local workflow static validation was not run.