chore: finalize issue templates (scoped titles + ordering) (#275)

[SamuelHassine]

Summary

Finalizes the issue templates across all Filigran repositories:

• Numeric-prefix ordering so the chooser is consistent everywhere.
• Scoped default titles (feat(scope): / fix(scope): , integration name for connectors/collectors/injectors) so new issues follow the Conventional Commits convention.
• Public config (native GitHub security reporting).

Closes #275

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 70.34%. Comparing base (ebe575f) to head (01bfcf6).
⚠️ Report is 1 commits behind head on main.

Additional details and impacted files

@@           Coverage Diff           @@
##             main     #276   +/-   ##
=======================================
  Coverage   70.34%   70.34%           
=======================================
  Files          49       49           
  Lines        1966     1966           
=======================================
  Hits         1383     1383           
  Misses        583      583           

Flag	Coverage Δ
connectors	70.34% <ø> (ø)

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