Initial commit: AutoBlogger v0.1.0

WordPress plugin that auto-researches topics from Reddit, generates
SEO-optimized articles via OpenRouter LLMs, runs them through a chief
editor agent, and publishes on a daily schedule.

Includes:
- Full generation pipeline (collect → analyze → score → generate → review → publish)
- Cost tracking and budget enforcement
- Admin UI: settings, review queue, metrics, activity log
- CI/CD pipeline (GitHub Actions → WordPress REST deploy)
- Unit test suite (PHPUnit + Brain Monkey)
- Structured logging with configurable verbosity

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

includes/providers/interface-source-provider.php

@@ -0,0 +1,58 @@
+<?php
+declare(strict_types=1);
+
+/**
+ * Contract for any social media source provider (Reddit, TikTok, Instagram, YouTube).
+ *
+ * Any class implementing this interface can be registered as a data source.
+ * The Source_Collector iterates through enabled providers and calls collect_data().
+ *
+ * @see class-reddit-provider.php     — Primary implementation (Reddit API).
+ * @see core/class-source-collector.php — Orchestrates collection from all providers.
+ * @see CONVENTIONS.md                — "How To: Add a New Source Provider".
+ */
+interface Autoblogger_Source_Provider_Interface {
+
+	/**
+	 * Collect posts/comments from this social platform.
+	 *
+	 * @param array{
+	 *     subreddits?: string[],
+	 *     limit?: int,
+	 *     time_filter?: string,
+	 *     keywords?: string[],
+	 * } $config Source-specific configuration.
+	 *
+	 * @return Autoblogger_Source_Data[] Array of collected data objects.
+	 *
+	 * @throws \RuntimeException On API error after retries exhausted.
+	 */
+	public function collect_data( array $config ): array;
+
+	/**
+	 * Get the source type identifier for this provider.
+	 *
+	 * Must match a valid value for ab_source_data.source_type.
+	 *
+	 * @return string Source type (e.g., 'reddit', 'tiktok', 'youtube').
+	 */
+	public function get_source_type(): string;
+
+	/**
+	 * Validate that the provider's API credentials are configured and working.
+	 *
+	 * @return bool True if credentials are valid and API is reachable.
+	 */
+	public function validate_credentials(): bool;
+
+	/**
+	 * Get current rate limit status for this provider's API.
+	 *
+	 * @return array{
+	 *     remaining: int,
+	 *     limit: int,
+	 *     resets_at: string,
+	 * } Rate limit information.
+	 */
+	public function get_rate_limit_status(): array;
+}