chore: rebrand as @supsys/discovery and update repository URLs

- Change package name from @astrojs/discovery to @supsys/discovery
- Update repository URL to git.supported.systems
- Update CHANGELOG references
- Rebuild and verify all tests pass (89/89)

.npmignore

@@ -0,0 +1,53 @@
+# Source files (dist/ is published via package.json "files" field)
+src/
+tests/
+*.test.ts
+*.spec.ts
+
+# Documentation site (separate deployment)
+docs/
+
+# Build artifacts
+*.tsbuildinfo
+.astro/
+node_modules/
+
+# Development files
+.vscode/
+.idea/
+*.log
+*.swp
+*.swo
+*~
+
+# Git
+.git/
+.gitignore
+.gitattributes
+
+# CI/CD
+.github/
+.gitlab-ci.yml
+.travis.yml
+
+# Development configs
+tsconfig.json
+vitest.config.ts
+.eslintrc*
+.prettierrc*
+
+# Testing
+coverage/
+.nyc_output/
+
+# Misc
+.DS_Store
+Thumbs.db
+.env
+.env.*
+
+# Project-specific
+status.json
+artifacts/
+PUBLISHING.md
+CLAUDE.md