docs: disable blank issues to enforce template + security routing

[rubenhensen]

Follow-up to #112 (already merged), addressing @dobby-coder's review nit on that PR.

Sets blank_issues_enabled: false in .github/ISSUE_TEMPLATE/config.yml. As Dobby noted, contact_links only add an entry to the issue chooser — with blank issues enabled, a contributor can still bypass the template and its security-advisory routing by opening a blank public issue. Disabling blank issues forces the chooser, which actually enforces the private security-report path that #102's SECURITY.md set up.

Ref #106.

[dobby-coder]

On it! I'll review PR #119 now and post a consolidated review with my verdict.

[dobby-coder]

Approving — clean, correct follow-up to #112.

blank_issues_enabled: false is the right fix for the nit I raised on #112: with blank issues enabled, contact_links only adds an entry to the chooser, so a contributor could still bypass the security-advisory routing by opening a blank public issue. Disabling blank issues forces the chooser, which enforces the private security-report path SECURITY.md (#102) set up.

• Config is valid: blank_issues_enabled is a supported top-level key and false is the correct value to disable blank issues; contact_links is untouched and still valid.
• Conventional-commit PR title (docs:) ✓, PR is ready-for-review (not draft) ✓.
• Config-only change with no runnable code affected — no tests to run.

Rule-compliance check (per-rule sweep) and diff review both found nothing actionable. Good to merge.

[dobby-coder]

Approved! This cleanly addresses the nit from #112 — with blank issues now disabled, the contact links are the only path forward, so the security advisory routing actually holds. No rule violations, nothing else to flag.