feat: initial MokoOpenGraph package scaffold

Joomla package (pkg_mokoog) with three sub-extensions:
- com_mokoog: Admin component with tag manager, MVC, database schema
- plg_system_mokoog: OG + Twitter Card meta tag injection via onBeforeCompileHead
- plg_content_mokoog: Per-article and per-menu-item OG fields in editor

Includes CI/CD workflows, issue templates, 12 feature issues, and
full Joomla 4/5 DI container architecture.

Authored-by: Moko Consulting

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

issues/001-batch-processing.md

@@ -0,0 +1,28 @@
+---
+title: "[FEATURE] Batch Processing — Generate OG Tags for All Existing Articles"
+labels: "enhancement, priority: high"
+milestone: "v01.01"
+---
+
+## Feature Description
+Add batch processing capability to generate or regenerate Open Graph tags for all existing articles in bulk, rather than requiring manual editing of each article.
+
+## Problem or Use Case
+When MokoOpenGraph is installed on an existing site with hundreds of articles, each article needs OG tags. Manually editing each one is impractical. Tagz Pro offers this as a premium feature — we should include it in the base package.
+
+## Proposed Solution
+Add a "Batch Generate" toolbar button to the com_mokoog admin view that:
+1. Scans all published articles in `#__content`
+2. For each article without existing OG data in `#__mokoog_tags`, auto-generates:
+   - `og_title` from article title
+   - `og_description` from meta description or intro text (first 160 chars)
+   - `og_image` from full-text image or intro image
+3. Shows a progress bar during processing
+4. Reports how many records were created/skipped
+
+## Implementation Details
+- New `Controller/BatchController.php` with `generate()` action
+- New `Model/BatchModel.php` for bulk operations
+- AJAX endpoint for progress reporting (avoid PHP timeout on large sites)
+- Process in chunks of 50 articles per request
+- Add batch button to `View/Tags/HtmlView.php` toolbar