refactor: Cleanup git state - commit all staged changes

Major refactoring cleanup:
- Add new controller architecture (class-controller-*.php)
- Add new settings-v2 UI (views/settings-v2/)
- Add new CSS architecture (agentic-sidebar.css, tokens)
- Add esbuild build pipeline (scripts/build.js, package.json)
- Add composer dependencies (vendor/)
- Add frontend src directory (assets/js/src/index.jsx)
- Add documentation files
- Remove old/obsolete files (class-settings.php, old CSS)

This commits all pending changes from previous refactoring efforts.

includes/class-memanto-client.php

@@ -42,6 +42,34 @@ class WP_Agentic_Writer_Memanto_Client
      */
     private $health_cache = null;
 
+    /**
+     * Circuit breaker transient key.
+     *
+     * @var string
+     */
+    private const CIRCUIT_TRANSIENT = "wpaw_memanto_circuit";
+
+    /**
+     * Circuit breaker timestamp transient key.
+     *
+     * @var string
+     */
+    private const CIRCUIT_SINCE_TRANSIENT = "wpaw_memanto_circuit_since";
+
+    /**
+     * Circuit breaker timeout in seconds (try again after this).
+     *
+     * @var int
+     */
+    private const CIRCUIT_TIMEOUT = 60;
+
+    /**
+     * Circuit breaker max duration in seconds (stay open max this long).
+     *
+     * @var int
+     */
+    private const CIRCUIT_MAX_DURATION = 300;
+
     /**
      * Get singleton instance.
      *
@@ -56,14 +84,85 @@ class WP_Agentic_Writer_Memanto_Client
     }
 
     /**
-     * Constructor.
+     * Create a one-off client for a specific base URL.
+     *
+     * @param string $base_url MEMANTO base URL.
+     * @return WP_Agentic_Writer_Memanto_Client
      */
-    private function __construct()
+    public static function for_base_url($base_url)
     {
+        return new self($base_url);
+    }
+
+    /**
+     * Constructor.
+     *
+     * @param string|null $base_url Optional MEMANTO base URL override.
+     */
+    private function __construct($base_url = null)
+    {
+        if (null !== $base_url) {
+            $this->base_url = untrailingslashit($base_url);
+            return;
+        }
+
         $settings = get_option("wp_agentic_writer_settings", []);
         $this->base_url = untrailingslashit($settings["memanto_url"] ?? "");
     }
 
+    // =========================================================================
+    // Circuit Breaker
+    // =========================================================================
+
+    /**
+     * Check if circuit breaker allows requests.
+     *
+     * @return bool True if circuit is closed (requests allowed), false if open (skip).
+     */
+    private function check_circuit_breaker()
+    {
+        $state = get_transient(self::CIRCUIT_TRANSIENT);
+
+        if ($state !== "open") {
+            return true;
+        }
+
+        // Circuit is open — check if timeout has passed.
+        $since = get_transient(self::CIRCUIT_SINCE_TRANSIENT);
+
+        if ($since && time() - $since < self::CIRCUIT_TIMEOUT) {
+            wpaw_debug_log("MEMANTO circuit breaker is open, skipping request");
+            return false;
+        }
+
+        // Timeout passed — try again (half-open state).
+        delete_transient(self::CIRCUIT_TRANSIENT);
+        delete_transient(self::CIRCUIT_SINCE_TRANSIENT);
+        wpaw_debug_log("MEMANTO circuit breaker resetting, attempting request");
+        return true;
+    }
+
+    /**
+     * Trip the circuit breaker (open state).
+     *
+     * Once open, requests are skipped for CIRCUIT_TIMEOUT seconds,
+     * then it retries. Max duration is CIRCUIT_MAX_DURATION.
+     */
+    private function trip_circuit_breaker()
+    {
+        set_transient(
+            self::CIRCUIT_TRANSIENT,
+            "open",
+            self::CIRCUIT_MAX_DURATION,
+        );
+        set_transient(
+            self::CIRCUIT_SINCE_TRANSIENT,
+            time(),
+            self::CIRCUIT_MAX_DURATION,
+        );
+        wpaw_debug_log("MEMANTO circuit breaker tripped");
+    }
+
     // =========================================================================
     // Configuration & Health
     // =========================================================================
@@ -98,6 +197,7 @@ class WP_Agentic_Writer_Memanto_Client
     {
         return $this->is_enabled() &&
             $this->is_configured() &&
+            $this->check_circuit_breaker() &&
             $this->is_healthy();
     }
 
@@ -527,7 +627,11 @@ class WP_Agentic_Writer_Memanto_Client
             "timeout" => 10,
         ]);
 
-        return $this->parse_response($response);
+        $result = $this->parse_response($response);
+        if (is_wp_error($result)) {
+            $this->trip_circuit_breaker();
+        }
+        return $result;
     }
 
     /**
@@ -575,7 +679,11 @@ class WP_Agentic_Writer_Memanto_Client
             }
         }
 
-        return $this->parse_response($response);
+        $result = $this->parse_response($response);
+        if (is_wp_error($result)) {
+            $this->trip_circuit_breaker();
+        }
+        return $result;
     }
 
     /**