chore: reorganize snippets into subdirectories

- move root gitignores into gitignores/ subdirectory
- add gitignores for dart, dotnet, go, gradle, java, jetbrains, maven, nextjs, node, sublimetext, vscode, windows, xcode
- add root .gitignore excluding .claude/settings.local.json
- add empty README.md and licences/ placeholders (Apache, MIT, Mozilla)

gitignores/SublimeText.gitignore

@@ -0,0 +1,32 @@
+### Sublime Text
+# Cache files for Sublime Text
+*.tmlanguage.cache
+*.tmPreferences.cache
+*.stTheme.cache
+
+# Workspace files are user-specific
+*.sublime-workspace
+
+# Project files should be checked into the repository, unless a significant
+# proportion of contributors will probably not be using Sublime Text
+# *.sublime-project
+
+# SFTP configuration file
+sftp-config.json
+sftp-config-alt*.json
+
+# Package control specific files
+Package Control.last-run
+Package Control.ca-list
+Package Control.ca-bundle
+Package Control.system-ca-bundle
+Package Control.cache/
+Package Control.ca-certs/
+Package Control.merged-ca-bundle
+Package Control.user-ca-bundle
+oscrypto-ca-bundle.crt
+bh_unicode_properties.cache
+
+# Sublime-github package stores a github token in this file
+# https://packagecontrol.io/packages/sublime-github
+GitHub.sublime-settings