PR Vision v0.2.0: admin/settings interface + correctness fixes (#3)

Model manager (UI-swappable models) + versioned/idempotent prv_models migration; metric comparability (config-version stamping); run-lock; projected cost + truncation state; per-model run-health; cadence reschedule; API-key 3-state; design/a11y fixes (dark v2).

QA: APPROVE-WITH-P2-NOTES — qa-reviews/pr-vision/2026-06-14-ee4371d9163f992f60e09c7e4ac6cf8cd1d3c5eb.md

Agent-Session: pr-vision admin v0.2.0 merge

includes/core/class-prv-upgrader.php

@@ -0,0 +1,40 @@
+<?php
+/**
+ * Upgrade runner: idempotent, version-gated migrations.
+ *
+ * @package PrVision
+ */
+
+declare(strict_types=1);
+
+/**
+ * Runs pending data migrations on every plugins_loaded call.
+ *
+ * Each migration is version-gated (cheap option check first) so it only
+ * runs when truly needed. Safe to call repeatedly -- all migrations are
+ * idempotent.  This fires on UPGRADE (not just activation), so the plugin
+ * running live on prod without a fresh activation still gets migrated.
+ *
+ * Who triggers: PRV_Plugin::init() at plugins_loaded priority 1.
+ * Dependencies: PRV_Model_Registry, PRV_Config_Version.
+ *
+ * @see class-prv-model-registry.php    -- Migration v2 implementation.
+ * @see class-prv-config-version.php    -- Scoring-config versioning.
+ * @see class-prv-plugin.php            -- Calls PRV_Upgrader::run().
+ * @package PrVision
+ */
+class PRV_Upgrader {
+
+	/**
+	 * Run all pending migrations in version order.
+	 *
+	 * Side effects: May write to wp_options (migration state).
+	 *
+	 * @return void
+	 */
+	public static function run(): void {
+		PRV_Table_Manager::create_table();
+		PRV_Model_Registry::run_migration_v2();
+		PRV_Config_Version::maybe_seed_initial_version();
+	}
+}