Add AI Performance Advisor plugin (#2485)

Introduce a new standalone feature plugin that surfaces actionable,
AI-generated performance recommendations in a dedicated Site Health tab.

The plugin gathers bounded site context through a pluggable provider
registry (environment, Site Health debug data with private fields removed,
plugin Site Health test results, a compact PageSpeed Insights snapshot, and
an optional Optimization Detective summary), sends it to the WordPress 7.0
AI Client API, and renders the returned recommendations as prioritized
cards. Analysis is on demand via an authenticated REST endpoint and the
result is cached in a transient to control token cost.

This initial version is suggest-only: it never changes site configuration.
The recommendation data model includes an optional, currently-inert
action.ability field so a future version can apply changes through the
Abilities API as that surface matures.

Includes unit tests (single site and multisite), registration in the
monorepo tooling and the Performance Lab feature list, and a PHPStan stub
for the WordPress 7.0 AI Client and Abilities APIs that are not yet present
in wordpress-stubs.

Fixes #2485

Author: adamsilverstein

.wp-env.json

@@ -2,6 +2,7 @@
 	"$schema": "https://schemas.wp.org/trunk/wp-env.json",
 	"core": null,
 	"plugins": [
+		"./plugins/ai-performance-advisor",
 		"./plugins/optimization-detective",
 		"./plugins/auto-sizes",
 		"./plugins/dominant-color-images",

composer.json

@@ -101,6 +101,7 @@
 			"WP_MULTISITE=1 php vendor/bin/phpunit --exclude-group=ms-excluded"
 		],
 		"test-multisite:plugins": [
+			"@test-multisite:ai-performance-advisor",
 			"@test-multisite:auto-sizes",
 			"@test-multisite:dominant-color-images",
 			"@test-multisite:embed-optimizer",
@@ -112,6 +113,7 @@
 			"@test-multisite:web-worker-offloading",
 			"@test-multisite:webp-uploads"
 		],
+		"test-multisite:ai-performance-advisor": "@test-multisite --verbose --testsuite ai-performance-advisor",
 		"test-multisite:auto-sizes": "@test-multisite --verbose --testsuite auto-sizes",
 		"test-multisite:dominant-color-images": "@test-multisite --verbose --testsuite dominant-color-images",
 		"test-multisite:embed-optimizer": "@test-multisite --verbose --testsuite embed-optimizer",
@@ -123,6 +125,7 @@
 		"test-multisite:web-worker-offloading": "@test-multisite --verbose --testsuite web-worker-offloading",
 		"test-multisite:webp-uploads": "@test-multisite --verbose --testsuite webp-uploads",
 		"test:plugins": [
+			"@test:ai-performance-advisor",
 			"@test:auto-sizes",
 			"@test:dominant-color-images",
 			"@test:embed-optimizer",
@@ -134,6 +137,7 @@
 			"@test:web-worker-offloading",
 			"@test:webp-uploads"
 		],
+		"test:ai-performance-advisor": "@test --verbose --testsuite ai-performance-advisor",
 		"test:auto-sizes": "@test --verbose --testsuite auto-sizes",
 		"test:dominant-color-images": "@test --verbose --testsuite dominant-color-images",
 		"test:embed-optimizer": "@test --verbose --testsuite embed-optimizer",

phpstan.neon.dist

@@ -18,6 +18,7 @@ parameters:
 		- vendor/phpstan/php-8-stubs/stubs/ext/standard/str_contains.php
 		- vendor/phpstan/php-8-stubs/stubs/ext/standard/str_starts_with.php
 		- vendor/phpstan/php-8-stubs/stubs/ext/standard/str_ends_with.php
+		- tools/phpstan/stubs/ai-client.stub
 	stubFiles:
 		- tools/phpstan/filtered-functions.stub
 	dynamicConstantNames:

phpunit.xml.dist

@@ -11,6 +11,9 @@
 		<testsuite name="performance-lab">
 			<directory suffix=".php">plugins/performance-lab/tests</directory>
 		</testsuite>
+		<testsuite name="ai-performance-advisor">
+			<directory suffix=".php">plugins/ai-performance-advisor/tests</directory>
+		</testsuite>
 		<testsuite name="auto-sizes">
 			<directory suffix=".php">plugins/auto-sizes/tests</directory>
 		</testsuite>

plugins.json

@@ -1,5 +1,6 @@
 {
 	"plugins": [
+		"ai-performance-advisor",
 		"auto-sizes",
 		"dominant-color-images",
 		"embed-optimizer",

plugins/ai-performance-advisor/css/analyzer.css

@@ -0,0 +1,90 @@
+/**
+ * AI Performance Advisor - Site Health tab styles.
+ *
+ * @since 1.0.0
+ */
+
+#aipa-results {
+	margin-top: 1em;
+}
+
+.aipa-card {
+	background: #fff;
+	border: 1px solid #c3c4c7;
+	border-left-width: 4px;
+	border-radius: 2px;
+	padding: 12px 16px;
+	margin-bottom: 12px;
+}
+
+.aipa-card.aipa-severity-critical {
+	border-left-color: #d63638;
+}
+
+.aipa-card.aipa-severity-recommended {
+	border-left-color: #dba617;
+}
+
+.aipa-card.aipa-severity-good {
+	border-left-color: #00a32a;
+}
+
+.aipa-card.aipa-severity-info {
+	border-left-color: #72aee6;
+}
+
+.aipa-card-title {
+	margin: 0 0 0.5em;
+	font-size: 1.05em;
+}
+
+.aipa-badge {
+	display: inline-block;
+	font-size: 11px;
+	line-height: 1.6;
+	text-transform: uppercase;
+	letter-spacing: 0.5px;
+	padding: 0 8px;
+	border-radius: 9px;
+	color: #fff;
+	vertical-align: middle;
+}
+
+.aipa-badge-critical {
+	background: #d63638;
+}
+
+.aipa-badge-recommended {
+	background: #dba617;
+}
+
+.aipa-badge-good {
+	background: #00a32a;
+}
+
+.aipa-badge-info {
+	background: #72aee6;
+}
+
+.aipa-card-summary {
+	margin: 0 0 0.5em;
+	font-weight: 600;
+}
+
+.aipa-card-details {
+	white-space: pre-wrap;
+	margin: 0 0 0.5em;
+}
+
+.aipa-card-evidence summary {
+	cursor: pointer;
+	color: #50575e;
+}
+
+.aipa-card-actions {
+	margin-top: 0.75em;
+}
+
+.aipa-card-actions .button {
+	margin-right: 8px;
+}