add CLAUDE.md, .gitignore, fix statusIcon rendering

- Add CLAUDE.md with build workflow, project overview, and key patterns
- Add .gitignore to prevent committing binaries and IDE files
- Remove hub.exe from tracking (was accidentally committed)
- Fix statusIcon: use Unicode ● character instead of HTML entities
  that get double-escaped by Go html/template

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

.gitignore

@@ -0,0 +1,30 @@
+# Go binaries
+hub/hub
+hub/hub.exe
+hub/bin/
+
+# Build artifacts
+*.exe
+*.dll
+*.so
+*.dylib
+
+# Test and coverage
+*.test
+*.out
+coverage.html
+
+# IDE
+.idea/
+.vscode/
+*.swp
+*.swo
+*~
+
+# OS
+.DS_Store
+Thumbs.db
+
+# Temporary files
+*.tmp
+*.bak