chore: ignore OS, IDE and Claude generated files

- Add OS ignore patterns for Linux, macOS and Windows
- Ignore JetBrains per-developer files, including the .idea/ directory
- Ignore the .claude/ directory
- Keep existing project ignores intact: local database, generated Prisma
  client, env files and build output

.gitignore

@@ -1,3 +1,97 @@
+### Linux
+*~
+.fuse_hidden*
+.directory
+.Trash-*
+.nfs*
+nohup.out
+
+### macOS
+.DS_Store
+.AppleDouble
+.LSOverride
+._*
+.DocumentRevisions-V100
+.fseventsd
+.Spotlight-V100
+.TemporaryItems
+.Trashes
+.VolumeIcon.icns
+.com.apple.timemachine.donotpresent
+.AppleDB
+.AppleDesktop
+Network Trash Folder
+Temporary Items
+.apdisk
+
+### Windows
+# Windows thumbnail cache files
+Thumbs.db
+Thumbs.db:encryptable
+ehthumbs.db
+ehthumbs_vista.db
+
+# Dump file
+*.stackdump
+
+# Folder config file
+[Dd]esktop.ini
+
+# Recycle Bin used on file shares
+$RECYCLE.BIN/
+
+# Windows Installer files
+*.cab
+*.msi
+*.msix
+*.msm
+*.msp
+
+# Windows shortcuts
+*.lnk
+
+### JetBrains
+# Covers JetBrains IDEs: IntelliJ, GoLand, RubyMine, PhpStorm, AppCode, PyCharm, CLion, Android Studio, WebStorm and Rider
+# Reference: https://intellij-support.jetbrains.com/hc/en-us/articles/206544839
+
+# User-specific stuff
+.idea/
+*.iml
+*.ipr
+
+# CMake
+cmake-build-*/
+
+# File-based project format
+*.iws
+
+# IntelliJ
+out/
+
+# mpeltonen/sbt-idea plugin
+.idea_modules/
+
+# JIRA plugin
+atlassian-ide-plugin.xml
+
+# Crashlytics plugin (for Android Studio and IntelliJ)
+com_crashlytics_export_strings.xml
+crashlytics.properties
+crashlytics-build.properties
+fabric.properties
+
+# Editor-based HTTP Client
+http-client.private.env.json
+
+# Android studio 3.1+ serialized cache file
+
+# Apifox Helper cache
+.idea/ApifoxUploaderProjectSetting.xml
+
+# Github Copilot persisted session migrations, see: https://github.com/microsoft/copilot-intellij-feedback/issues/712#issuecomment-3322062215
+
+### Next.js
+
 # See https://help.github.com/articles/ignoring-files/ for more about ignoring files.
 
 # dependencies
@@ -21,7 +115,6 @@
 /build
 
 # misc
-.DS_Store
 *.pem
 
 # debug
@@ -44,5 +137,7 @@ yarn-error.log*
 *.tsbuildinfo
 next-env.d.ts
 
-# prisma generated client (regenerated by `prisma generate`)
+# Claude Code
-/lib/generated
+.claude/
+
+/lib/generated/