Add plugin repository packaging and manifest metadata.

Include a .gitignore for .NET plugin development and a packaging script that produces Jellyfin-compatible zip artifacts with checksums and manifest updates for catalog installation.

Made-with: Cursor

.gitignore

@@ -0,0 +1,39 @@
+# Build outputs
+bin/
+obj/
+artifacts/
+
+# User-specific files
+*.user
+*.rsuser
+*.suo
+*.userprefs
+
+# IDE/editor files
+.idea/
+.vscode/
+*.swp
+*.swo
+*~
+
+# OS files
+.DS_Store
+Thumbs.db
+
+# Logs and temp
+*.log
+*.tmp
+*.temp
+
+# .NET test and coverage artifacts
+TestResults/
+*.trx
+*.coverage
+*.coveragexml
+coverage/
+
+# NuGet
+packages/
+*.nupkg
+*.snupkg
+