Bundle Twilio + AWS SDKs in releases, add SNS install path

Gitea release workflow now runs composer install --no-dev before zipping, so
each release ships vendor/ with both Twilio and AWS SDKs. The plugin's loader
priority is flipped to match: internal vendor/autoload.php first (always
current after every plugin update), external wp-content/twilio-sdk/ second
(legacy/manual install fallback).

AWS SDK detection wired in alongside Twilio: composer's bundled autoloader
covers Aws\… natively when present; otherwise plugin falls back to a new
external location wp-content/aws-sdk/ via install-aws-sdk-external.sh, which
drops the AWS SDK PHAR with a tiny autoload shim. AWS-missing admin notice
fires only when twp_sms_provider === 'aws_sns' so existing Twilio SMS users
see no new noise.

Loader priority flip applied in three places that all had the same
external-first pattern: twilio-wp-plugin.php (twp_check_sdk_installation),
class-twp-twilio-api.php (init_sdk_client), class-twp-webhooks.php
(constructor). twp_check_sdk_after_update messaging updated to reflect that
plugin updates now bundle the SDK.

Files:
  .gitea/workflows/release.yml      — composer install before ZIP
  twilio-wp-plugin.php              — TWP_EXTERNAL_AWS_SDK_DIR, dual-SDK
                                      detection, twp_aws_sdk_missing_notice
  includes/class-twp-twilio-api.php — internal-first autoloader
  includes/class-twp-webhooks.php   — internal-first autoloader
  install-aws-sdk-external.sh       — new AWS SDK PHAR installer

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

.gitea/workflows/release.yml

@@ -16,6 +16,15 @@ jobs:
           password: ${{ secrets.CI_TOKEN }}
           fetch-depth: 0  # Important: Fetch all history for commit messages
 
+      - name: Setup PHP
+        uses: shivammathur/setup-php@v2
+        with:
+          php-version: '8.0'
+          tools: composer
+
+      - name: Install Composer dependencies
+        run: composer install --no-dev --prefer-dist --optimize-autoloader --no-interaction
+
       - name: Get version
         id: get_version
         run: |