chore(linting): refresh configs and sweep auto-fix

Pull in the refreshed linter and tooling configs (editorconfig,
gitignore, gitattributes, prettierignore, prettierrc, markdownlint,
yamllint, env.example, dotnet-tools) and run prettier and markdownlint
in --fix / --write mode across the repo so the existing tree matches
the new rules.

- prettier 2-space indent on yaml/yml and json overrides, asterisk
  strong, underscore emphasis, proseWrap always
- markdownlint MD007 indent aligned to 2 and MD049 to underscore so
  prettier output stays passing
- preflight Block F also ignores CLAUDE.md (gitignored personal file)
- prettierignore extended to keep HellionChat.yaml manifest and the
  NuGet packages.lock.json out of the formatter

No semantic content changed; csharpier, build, full build-suite
(729/729) and the new prettier/markdownlint/yamllint checks all green.

.github/ISSUE_TEMPLATE/feature_request.yml

@@ -1,57 +1,55 @@
 name: Feature request
 description: Suggest a feature or enhancement for HellionChat
 labels:
-    - enhancement
+  - enhancement
 body:
-    - type: markdown
-      attributes:
-          value: |
-              Thanks for the suggestion. HellionChat focuses on privacy by
-              default and a small, well-scoped feature set. Suggestions that
-              align with that scope are easier to accept than ones that pull
-              the plugin toward "do everything".
+  - type: markdown
+    attributes:
+      value: |
+        Thanks for the suggestion. HellionChat focuses on privacy by
+        default and a small, well-scoped feature set. Suggestions that
+        align with that scope are easier to accept than ones that pull
+        the plugin toward "do everything".
 
-    - type: textarea
-      id: problem
-      attributes:
-          label: What problem are you trying to solve
-          description: The user-side problem, not the proposed solution yet
-      validations:
+  - type: textarea
+    id: problem
+    attributes:
+      label: What problem are you trying to solve
+      description: The user-side problem, not the proposed solution yet
+    validations:
+      required: true
+
+  - type: textarea
+    id: solution
+    attributes:
+      label: What you would like HellionChat to do
+    validations:
+      required: true
+
+  - type: textarea
+    id: alternatives
+    attributes:
+      label: Alternatives you have considered
+      description: Other plugins, manual workarounds, settings combinations
+
+  - type: dropdown
+    id: scope
+    attributes:
+      label: Scope estimate from your side
+      options:
+        - 'Small (one tab, one toggle, one filter)'
+        - 'Medium (a settings section, persistent state, one new file)'
+        - 'Large (architectural, touches the message pipeline or the database)'
+        - "I don't know"
+    validations:
+      required: true
+
+  - type: checkboxes
+    id: confirm
+    attributes:
+      label: Pre-flight
+      options:
+        - label: I have searched existing issues for similar requests
           required: true
-
-    - type: textarea
-      id: solution
-      attributes:
-          label: What you would like HellionChat to do
-      validations:
+        - label: I understand HellionChat is a privacy-focused fork and not a feature parity tool with upstream Chat 2
           required: true
-
-    - type: textarea
-      id: alternatives
-      attributes:
-          label: Alternatives you have considered
-          description: Other plugins, manual workarounds, settings combinations
-
-    - type: dropdown
-      id: scope
-      attributes:
-          label: Scope estimate from your side
-          options:
-              - "Small (one tab, one toggle, one filter)"
-              - "Medium (a settings section, persistent state, one new file)"
-              - "Large (architectural, touches the message pipeline or the database)"
-              - "I don't know"
-      validations:
-          required: true
-
-    - type: checkboxes
-      id: confirm
-      attributes:
-          label: Pre-flight
-          options:
-              - label: I have searched existing issues for similar requests
-                required: true
-              - label:
-                    I understand HellionChat is a privacy-focused fork and not a feature parity tool with upstream Chat
-                    2
-                required: true