ci: single-workflow Friday train (train.yml)

[vreshch]

Summary

• Adds .github/workflows/train.yml per the Friday Train v2 spec: L2 deploy-only, minimal variant for vreshch.com.
• Job deps merges green dependabot PRs, exposes merged_count as a job output.
• Job deploy runs only when merged_count > 0, dispatching deploy.yml (which runs its own build; PRs were already gated by pr-validation.yml).
• Cron 0 21 * * 5 (L2 slot). Single input bump_deps (boolean, default true).
• Permissions: contents: write, pull-requests: write, actions: write.
• Nothing deleted - additive only.

Test plan

• bash -n on all run: blocks
• npx @action-validator/cli clean
• npm run format:check clean
• CI green on this PR (pr-validation.yml)
• Post-merge dispatch of train.yml completes green

[github-actions]

🎉 PR Validation ✅ PASSED

Commit: 23448283bf481d851bca4a93d99d6b4eaff466db
Branch: feature/train-v2

Checks:

• ✅ Dependencies installed
• ✅ Linting passed
• ✅ Format check passed
• ✅ Build successful
• ✅ Docker build
• ✅ E2E tests

Visual Changes: 8 of 8 screenshots changed

📸 contacts desktop — 100% changed

📸 contacts mobile — 100% changed

📸 home desktop — 100% changed

📸 home mobile — 100% changed

📸 interests desktop — 100% changed

📸 interests mobile — 100% changed

📸 projects desktop — 100% changed

📸 projects mobile — 100% changed

Ready to merge! ✨

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🔗 View workflow run
⏰ Generated at: 2026-08-10T21:07:03.791Z