feat: Polar license key integration and dashboard UI improvements

- Add license activation flow: server validates/activates keys via Polar SDK
- Auto-activate from Polar checkout redirect (checkout_id in URL)
- Gate dashboard behind license activation (redirect to /activate if no plan)
- Preserve redirect URL through login flow for post-purchase activation
- Show plan status badge in sidebar and overview page
- Add account section to settings (email, plan, license key)
- Add svelte-sonner toasts with custom black theme and iconify icons
- Improve validation messages across all forms
- Update API key prefix to droidclaw_
- Add cursor pointer globally for clickable elements
- Support Polar sandbox mode via POLAR_SANDBOX env flag

web/package.json

@@ -52,8 +52,13 @@
 		"vitest-browser-svelte": "^1.1.0"
 	},
 	"dependencies": {
+		"@iconify/svelte": "^5.2.1",
+		"add": "^2.0.6",
 		"better-auth": "^1.3.27",
 		"postgres": "^3.4.7",
+		"shadcn-svelte": "^1.1.1",
+		"sonner": "^2.0.7",
+		"svelte-sonner": "^1.0.7",
 		"valibot": "^1.1.0"
 	}
 }