Chore: Create issue templates (bug report, feature request)

[Lansa-18]

Summary

Added structured GitHub issue templates to replace the default blank text box. Contributors are now guided through required fields when filing bugs or requesting features. Blank issues are disabled via config.yml to enforce template use.

Closes #209

Type of change

• feat
• fix
• docs
• chore
• test
• ci

Testing performed

No code changes — new YAML files only. Verified locally:

All 4 packages — 0 errors, 0 new warnings

cd api && npm run lint && npx tsc --noEmit
cd xstreamroll-sdk && npm run lint && npx tsc --noEmit
cd xstreamroll-processing && npm run lint && npx tsc --noEmit
cd app && npm run lint && npx tsc --noEmit

Final verification on GitHub: open a new issue and confirm the template chooser appears, blank issue link is absent, and required fields block empty submission.

Screenshots (if applicable)

N/A — no UI changes.

Checklist — author

• I rebased onto origin/main and resolved conflicts.
• I ran the quality gates locally: npm run lint, npm run build, npm test.
• Title follows Conventional Commits and references the issue (see above).
• I added/updated tests where applicable and they pass locally.
• No new TypeScript errors or lint warnings introduced.
• I updated documentation if the change affects public behavior.
• Screenshots included for UI changes.

Checklist — reviewer guidance

• Required checks: lint, build, unit tests, and any package-specific E2E must be green.
• Request review from CODEOWNER(s) for touched packages.
• Prefer small, focused PRs. If large, confirm feature-flagging or follow-up tasks.

---

The two unchecked checklist items (tests and documentation) are intentionally left unchecked — there are no tests to write for YAML template files, and no public behavior changed that needs documenting.

[Lansa-18]

@Xhristin3 Kindly go through.

[Xhristin3]

Thanks for setting up the issue templates — this will go a long way toward keeping our bug reports and feature requests structured. Approving and merging!