feat: wire Resend mail and Cloudflare R2 storage (#4)

Add production provider deps/config so transactional email and CMS
media can use Resend and a dedicated r2 disk with custom-domain URLs.

Co-authored-by: Cursor <cursoragent@cursor.com>

openspec/changes/add-production-providers/proposal.md

@@ -0,0 +1,43 @@
+## Why
+
+The application already supports CMS media uploads and will soon send transactional email (lead notifications, password reset), but production still lacks concrete provider wiring. SPEC §9.1 and §15.4 require S3-compatible object storage in production and transactional email when configured. Resend and Cloudflare R2 are the chosen providers; this change adds the configuration, dependencies, and selection rules so production can send mail and persist public media outside the container filesystem.
+
+## What Changes
+
+- Add **Resend** as the production mail transport via Laravel's native `resend` mailer and `RESEND_API_KEY`.
+- Add a dedicated **`r2` filesystem disk** for Cloudflare R2 (S3-compatible API) with explicit R2 env vars and public URLs served through a **custom domain** (`R2_URL`).
+- Install required dependencies: `resend/resend-php` and `league/flysystem-aws-s3-v3`.
+- Update `.env.example`, README, and deployment guidance with production vs local/test defaults.
+- Fix media disk selection in `PublicImageUploadRules` so `FILESYSTEM_DISK=r2` uses the R2 disk instead of falling back to local `public`.
+- Add automated config and media-disk selection tests; no live calls to Resend or R2 in CI.
+
+## Non-Goals
+
+Conforme [SPEC.md §4.2](../../SPEC.md), **não** fazem parte desta change:
+
+- Lead notification emails, briefing confirmation flows, or CRM email templates (future phases).
+- Private/signed URL access to media; production media is public via custom domain.
+- Cloudflare Workers, CDN provisioning, or DNS automation (manual infra setup).
+- Redis, queue driver changes, or FrankenPHP worker mode.
+- Replacing local `public` disk behavior for development and tests.
+
+## Capabilities
+
+### New Capabilities
+
+- `transactional-email`: Resend-backed transactional mail transport with safe local/test defaults and production configuration via environment variables (SPEC §9.1, §15.4, §12.1–12.2).
+- `object-storage`: Cloudflare R2 object storage via dedicated `r2` disk, custom-domain public URLs, and environment-driven disk selection (SPEC §6.4, §9.1, §15.4).
+
+### Modified Capabilities
+
+- `content-media`: extend disk selection so production `FILESYSTEM_DISK=r2` stores and serves public content images from R2 instead of local `public`.
+
+## Impact
+
+- **Dependencies**: `resend/resend-php`, `league/flysystem-aws-s3-v3` in `composer.json`.
+- **Config**: `config/mail.php`, `config/services.php`, `config/filesystems.php`, `.env.example`.
+- **Application**: `app/Support/PublicImageUploadRules.php` disk selection logic.
+- **Tests**: new Pest feature/unit tests for mail and filesystem config; media disk selection regression test.
+- **Docs**: `README.md` production provider section.
+- **Infra (manual)**: Resend API key, R2 bucket, R2 API token, and custom domain mapped to the bucket.
+- **No breaking change** for local development: defaults remain `MAIL_MAILER=log` and `FILESYSTEM_DISK=local`/`public`.