chore: expand gitignore to cross-platform template

- ignore OS and editor noise for Linux, macOS, and Windows (.DS_Store, Thumbs.db, *~, etc.)
- ignore the entire .idea/ IDE folder instead of per-file rules
- keep Rust build output (target/, debug) ignored

.gitignore

@@ -1 +1,134 @@
-/target
+### Linux
+
+*~
+
+# temporary files which can be created if a process still has a handle open of a deleted file
+.fuse_hidden*
+
+# Metadata left by Dolphin file manager, which comes with KDE Plasma
+.directory
+
+# Linux trash folder which might appear on any partition or disk
+.Trash-*
+
+# .nfs files are created when an open file is removed but is still being accessed
+.nfs*
+
+# Log files created by default by the nohup command
+nohup.out
+
+### macOS
+
+# General
+.DS_Store
+.localized
+__MACOSX/
+.AppleDouble
+.LSOverride
+Icon[
+]
+
+# Resource forks
+._*
+
+# Files and directories that might appear in the root of a volume
+.DocumentRevisions-V100
+.fseventsd
+.Spotlight-V100
+.TemporaryItems
+.Trashes
+.VolumeIcon.icns
+.com.apple.timemachine.donotpresent
+.com.apple.timemachine.supported
+.PKInstallSandboxManager
+.PKInstallSandboxManager-SystemSoftware
+.hotfiles.btree
+.vol
+.file
+.disk_label*
+lost+found
+.HFS+ Private Directory Data[
+]
+
+# Directories potentially created on remote AFP share
+.AppleDB
+.AppleDesktop
+Network Trash Folder
+Temporary Items
+.apdisk
+
+# Mac OS 6 to 9
+Desktop DB
+Desktop DF
+TheFindByContentFolder
+TheVolumeSettingsFolder
+.FBCIndex
+.FBCSemaphoreFile
+.FBCLockFolder
+
+# Quota system
+.quota.group
+.quota.user
+.quota.ops.group
+.quota.ops.user
+
+# TimeMachine
+Backups.backupdb
+.MobileBackups
+.MobileBackups.trash
+MobileBackups.trash
+tmbootpicker.efi
+
+### 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
+
+### Rust
+
+# Generated by Cargo
+# will have compiled files and executables
+debug
+target
+
+# These are backup files generated by rustfmt
+**/*.rs.bk
+
+# MSVC Windows builds of rustc generate these, which store debugging information
+*.pdb
+
+# Generated by cargo mutants
+# Contains mutation testing data
+**/mutants.out*/
+
+# rustc will dump stack traces when hitting an internal compiler error to PWD
+rustc-ice-*.txt
+
+# RustRover
+#  JetBrains specific template is maintained in a separate JetBrains.gitignore that can
+#  be found at https://github.com/github/gitignore/blob/main/Global/JetBrains.gitignore
+#  and can be added to the global gitignore or merged into this file.  For a more nuclear
+#  option (not recommended) you can uncomment the following to ignore the entire idea folder.
+.idea/