perf & ux : cache getAll, fingerprint assets, Last-Modified, 404 log, row-click bulk (v1.6.19)

- getAll() : cache fichier articles_list.json, invalidé à chaque écriture (#16)
- layout.php : fingerprinting ?v=<hash> sur CSS/JS pour invalidation navigateur (#18)
- case 'view' : Last-Modified + 304 Not Modified pour les articles publiés (#18)
- case 'not_found' : logging JSON des 404 dans _logs/not_found.jsonl (#52)
- case 'view' : echo nu → templates/404.php pour brouillons/privés (#52)
- admin.js : clic sur ligne tableau → toggle bulk-check (#86)

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

src/ArticleManager.php

@@ -30,6 +30,14 @@ class ArticleManager
 
     private function loadAll(): array
     {
+        $cachePath = $this->allListCachePath();
+        if (file_exists($cachePath)) {
+            $cached = json_decode((string)file_get_contents($cachePath), true);
+            if (is_array($cached) && $cached !== []) {
+                return $cached;
+            }
+        }
+
         $articles = [];
         if (!is_dir($this->dataDir)) {
             return $articles;
@@ -66,6 +74,12 @@ class ArticleManager
             }
         }
 
+        $cacheDir = dirname($cachePath);
+        if (!is_dir($cacheDir)) {
+            @mkdir($cacheDir, 0755, true);
+        }
+        @file_put_contents($cachePath, json_encode($articles, JSON_UNESCAPED_UNICODE | JSON_UNESCAPED_SLASHES));
+
         return $articles;
     }
 
@@ -849,6 +863,7 @@ class ArticleManager
             $this->allCache = null;
             @unlink($this->articleCachePath($uuid));
             @unlink($this->slugIndexPath());
+            @unlink($this->allListCachePath());
             $this->removeDir($dir);
         }
         if (is_dir($dir)) {
@@ -879,6 +894,11 @@ class ArticleManager
         return $this->dataDir . '/_cache/slug_index.json';
     }
 
+    private function allListCachePath(): string
+    {
+        return $this->dataDir . '/_cache/articles_list.json';
+    }
+
     private function buildSlugIndex(): void
     {
         $cacheDir = $this->dataDir . '/_cache';
@@ -1343,9 +1363,10 @@ class ArticleManager
         $this->searchIndexCache = null;
         $uuid = $meta['uuid'] ?? basename($dir);
 
-        // Invalider le cache article et le slug index
+        // Invalider les caches article, liste et slug index
         @unlink($this->articleCachePath($uuid));
         @unlink($this->slugIndexPath());
+        @unlink($this->allListCachePath());
 
         file_put_contents(
             $dir . '/meta.json',