chore: remove title prefixes from issue templates (#94)

Users report bugs and request features — they shouldn't need to know
conventional commit types. The Feature Planner adds the correct prefix
(feat:/fix:) during triage based on the template's label.

Co-authored-by: Ona <no-reply@ona.com>

Author: zacharias-ona

.github/ISSUE_TEMPLATE/bug.yml

@@ -1,6 +1,5 @@
 name: Bug Report
 description: Report a bug or unexpected behavior
-title: "fix: "
 labels: ["bug"]
 body:
   - type: markdown

.github/ISSUE_TEMPLATE/feature.yml

@@ -1,6 +1,5 @@
 name: Feature Request
 description: Suggest a new feature or enhancement
-title: "feat: "
 labels: []
 body:
   - type: markdown