Refactor and update various components of EchoHub.Server

- Updated launchSettings.json for consistency.
- Refactored FileValidationHelper to improve image validation logic.
- Enhanced ServerDirectoryService for better connection handling and user count updates.
- Improved DatabaseSetup for legacy database handling and seeding default channels.
- Refined FirstRunSetup to ensure JWT secret generation.
- Removed appsettings.Development.json as it is no longer needed.
- Updated EchoHub.Tests project file for consistency.
- Added unit tests for FileValidationHelper and PresenceTracker with improved assertions.
- Updated ValidationConstantsTests to ensure regex validations are correct.
- Cleaned up solution file formatting for better readability.

.github/ISSUE_TEMPLATE/feature_request.yml

@@ -1,51 +1,51 @@
-name: Feature request
-description: Suggest an idea or improvement
-title: "feat: "
-labels: [enhancement]
-body:
-  - type: markdown
-    attributes:
-      value: |
-        Thanks for suggesting an improvement.
-
-        EchoHub tries to stay lightweight: terminal-first, self-hosted, and no upsells.
-
-  - type: dropdown
-    id: area
-    attributes:
-      label: Area
-      options:
-        - Client (TUI)
-        - Server (API/SignalR)
-        - Auth/security
-        - Files/uploads
-        - Docs
-        - Build/CI
-    validations:
-      required: true
-
-  - type: textarea
-    id: problem
-    attributes:
-      label: What problem are you trying to solve?
-      placeholder: "It’s hard to..., because ..."
-    validations:
-      required: true
-
-  - type: textarea
-    id: proposal
-    attributes:
-      label: Proposed solution
-      placeholder: "Add/Change ..., so that ..."
-
-  - type: textarea
-    id: alternatives
-    attributes:
-      label: Alternatives considered
-      description: Any other approaches you’ve thought about.
-
-  - type: textarea
-    id: extra
-    attributes:
-      label: Additional context
-      description: Mockups, examples, links, etc.
+name: Feature request
+description: Suggest an idea or improvement
+title: "feat: "
+labels: [enhancement]
+body:
+  - type: markdown
+    attributes:
+      value: |
+        Thanks for suggesting an improvement.
+
+        EchoHub tries to stay lightweight: terminal-first, self-hosted, and no upsells.
+
+  - type: dropdown
+    id: area
+    attributes:
+      label: Area
+      options:
+        - Client (TUI)
+        - Server (API/SignalR)
+        - Auth/security
+        - Files/uploads
+        - Docs
+        - Build/CI
+    validations:
+      required: true
+
+  - type: textarea
+    id: problem
+    attributes:
+      label: What problem are you trying to solve?
+      placeholder: "It’s hard to..., because ..."
+    validations:
+      required: true
+
+  - type: textarea
+    id: proposal
+    attributes:
+      label: Proposed solution
+      placeholder: "Add/Change ..., so that ..."
+
+  - type: textarea
+    id: alternatives
+    attributes:
+      label: Alternatives considered
+      description: Any other approaches you’ve thought about.
+
+  - type: textarea
+    id: extra
+    attributes:
+      label: Additional context
+      description: Mockups, examples, links, etc.