docs: prefill issue titles with Conventional Commits format (#13750)

bug_report.yml and feature_request.yml prefilled `[BUG] ` / `[Feature] ` while
CONTRIBUTING.md documents Conventional Commits with a scope list, so reporters
who followed the template verbatim had their title renamed by triage. The
templates now teach the convention instead: `fix(): ` and `feat(): `.

Each form gains one intro line pointing at the commit-message section of
CONTRIBUTING.md, where the scope list lives. `test_coverage_task.yml` is left
untouched, as its `[Coverage] ` prefix is not part of the convention.

Refs #13688

.github/ISSUE_TEMPLATE/bug_report.yml

@@ -1,6 +1,6 @@
 name: Bug Report
 description: Report a bug or unexpected behavior in OmniRoute
-title: "[BUG] "
+title: "fix(): "
 labels: ["bug"]
 body:
   - type: markdown
@@ -8,6 +8,8 @@ body:
       value: |
         Thanks for taking the time to report a bug. Please fill out the sections below so we can reproduce and fix the issue.
 
+        The title is prefilled as `fix(): ` to match the [Conventional Commits](https://github.com/diegosouzapw/OmniRoute/blob/main/CONTRIBUTING.md#commit-messages) convention — pick a scope from the list documented there (e.g. `providers`, `resilience`, `dashboard`, `api`).
+
   - type: input
     id: version
     attributes:

.github/ISSUE_TEMPLATE/feature_request.yml

@@ -1,6 +1,6 @@
 name: Feature Request
 description: Suggest a new feature or improvement for OmniRoute
-title: "[Feature] "
+title: "feat(): "
 labels: ["enhancement"]
 body:
   - type: markdown
@@ -8,6 +8,8 @@ body:
       value: |
         Thanks for suggesting a feature! Please describe the problem you're trying to solve and how you'd like it to work.
 
+        The title is prefilled as `feat(): ` to match the [Conventional Commits](https://github.com/diegosouzapw/OmniRoute/blob/main/CONTRIBUTING.md#commit-messages) convention — pick a scope from the list documented there (e.g. `providers`, `resilience`, `dashboard`, `api`).
+
   - type: textarea
     id: problem
     attributes: