feat(flutter-cursor-templates): introduce MCP integration and conventions in project brief

- Added optional MCP integration settings in project-brief.yaml, allowing for environment-based server configurations.
- Introduced conventions for strict package imports to enhance code organization and maintainability.
- Updated brief schema to validate new MCP properties and ensure correct usage.
- Implemented MCP JSON builder to generate .cursor/mcp.json based on project brief settings.
- Enhanced resolver to include MCP configuration in generated files when enabled.

This update improves integration capabilities and enforces coding standards across the project.

flutter-cursor-templates/templates/rules/integrations/push-deeplink.mdc.tmpl

@@ -0,0 +1,21 @@
+---
+description: Push notifications and deep linking for {{PROJECT_NAME}}
+globs: ["lib/**/*.dart", "android/**", "ios/**", "test/**/*.dart"]
+alwaysApply: false
+---
+
+# Push & deep linking — {{PROJECT_NAME}}
+
+## Context
+Special capabilities from `project-brief.yaml`: **{{SPECIAL_FEATURES}}**. Native and server configuration must stay consistent.
+
+## Constraints
+- **Push:** request permissions through the platform flow; handle denial gracefully; no silent failures on token registration
+- **Routing:** deep links and notification taps MUST go through **{{ROUTING}}** (no ad-hoc `Navigator` stacks for inbound links)
+- **Payloads:** map FCM/APNs/Supabase payloads to domain models in the data layer — no JSON parsing scattered in widgets
+- **iOS:** exercise push on a **physical device** when possible (simulator limitations)
+- **Android:** declare required permissions explicitly; target API behaviour for POST_NOTIFICATIONS where applicable
+
+## Testing
+- Unit-test payload → domain mapping and routing targets
+- Integration/E2E: cold start, background, and foreground tap-to-open flows when `testing.depth` allows