v1.20.0

✨ Features

• Plugins: add getSettingsUrl() and registerExtension() to BlogrExtension interface (renamed from register() to avoid FilamentPlugin collision)
• Plugins: add settings gear icon ⚙️ on each plugin card, linked to getSettingsUrl() when defined
• Plugins: add Community Plugins discovery section — parses README.md plugins table with GitHub/GitLab links
• Plugins: filter out already-installed plugins from community listing by repo name or homepage URL
• Plugins: add "Develop a Plugin" section with link to developing guide
• Docs: add ## Developing Plugins section to README with interface reference, registration, and lifecycle

🐛 Fixed

• Plugins: fix enable/disable toggles having no effect — register(Panel) now queries blogr_extension_states directly (bypasses singleton timing issue)
• Plugins: fix RouteNotFoundException when toggling a plugin on — getSettingsUrl() catches missing routes gracefully
• Plugins: fix loadedFromDb flag in ExtensionRegistry::loadStatesIfNeeded() being set before DB query
• Plugins: prevent auto-resolution of throwaway ExtensionRegistry instance when called before singleton registration
• Artist/Comms/GDPR: add shouldRegisterNavigation() to settings pages — navigation respects enable/disable state
• Artist/Comms/GDPR: move $panel->plugin() registration to register() phase so routes exist before navigation rendering