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-llm-provider.php

@@ -0,0 +1,71 @@
+<?php
+declare(strict_types=1);
+
+/**
+ * Contract for any LLM provider integration (OpenRouter, direct Anthropic, OpenAI, etc.).
+ *
+ * Any class implementing this interface can be swapped in without changing the
+ * content generation, analysis, or editor logic.
+ *
+ * @see class-openrouter-provider.php — Primary implementation (OpenRouter).
+ * @see CONVENTIONS.md                — "How To: Add a New LLM Provider".
+ * @see ARCHITECTURE.md               — External API integrations table.
+ */
+interface Autoblogger_LLM_Provider_Interface {
+
+	/**
+	 * Send a chat completion request to the LLM.
+	 *
+	 * @param array<int, array{role: string, content: string}> $messages Chat messages array.
+	 * @param string $model   Model identifier (e.g., 'anthropic/claude-sonnet-4').
+	 * @param array{
+	 *     temperature?: float,
+	 *     max_tokens?: int,
+	 *     response_format?: array{type: string},
+	 * } $options Optional parameters for the API call.
+	 *
+	 * @return array{
+	 *     content: string,
+	 *     model: string,
+	 *     prompt_tokens: int,
+	 *     completion_tokens: int,
+	 *     total_tokens: int,
+	 *     finish_reason: string,
+	 * } Normalized response.
+	 *
+	 * @throws \RuntimeException On API error after retries exhausted.
+	 */
+	public function send_chat_completion( array $messages, string $model, array $options = [] ): array;
+
+	/**
+	 * Get the list of available models from the provider.
+	 *
+	 * @return array<int, array{id: string, name: string, context_length: int, pricing: array{prompt: float, completion: float}}> Available models.
+	 */
+	public function get_available_models(): array;
+
+	/**
+	 * Estimate the cost of an API call based on token counts.
+	 *
+	 * @param string $model            Model identifier.
+	 * @param int    $prompt_tokens     Number of input tokens.
+	 * @param int    $completion_tokens Number of output tokens.
+	 *
+	 * @return float Estimated cost in USD.
+	 */
+	public function estimate_cost( string $model, int $prompt_tokens, int $completion_tokens ): float;
+
+	/**
+	 * Get the human-readable name of this provider.
+	 *
+	 * @return string Provider name (e.g., 'OpenRouter').
+	 */
+	public function get_provider_name(): string;
+
+	/**
+	 * Validate that the provider's credentials are configured and working.
+	 *
+	 * @return bool True if credentials are valid.
+	 */
+	public function validate_credentials(): bool;
+}