[1.1.0] Added icons

[unurgunite]

Summary

GUI stability fixes, app icon, test expansion, and YARD docs cleanup.

Changes

• Crash fix: removed free_table_model from on_closing (freed while tables alive -> SIGTRAP)
• Clean exit: UIng.init/UIng.main (no uiUninit — libui leak-detector aborts on macOS)
• cmd+Q / cmd+W: ObjC JBUpdaterHelper menu bar with uiQuit() (bypasses libui's broken terminate: override). Works for bare binary + .app
• Dock icon: NSApp setApplicationIconImage: via ObjC bridge + assets/jb_updater.icns
• Icons: SVG -> .icns macOS, .ico Windows, PNGs. Bundled in CI (.app + Linux archive)
• parse_cli: optional argv parameter for testability
• PluginInfo: removed nil types from @categories/@tags (always [] of String)
• Specs: cli_spec, plugin_marketplace_spec (new), expanded plugin_meta_spec, http_client_spec. 91 examples, 0 failures
• Shared helpers: spec/support/tmpdir.cr (Rails-style)
• YARD: improved @param/@return on html_strip, PluginInfo constructor
• Ameba: 26 files, 0 offenses

Verification

• crystal spec passes
• bin/ameba — 0 offenses