feat: professional repo cleanup + community infrastructure

- README: remove Recent Updates section, clean roadmap (pending only),
  replace Screenshots with demo link, add 6 new badges (stars, last
  commit, contributors, discussions, CI), invite GIF contributions
- CHANGELOG: translate all Italian entries to English, add v1.7.13
  (DB fresh-install crash fix)
- database.php: add missing 'undone' column to transactions schema;
  wrap ALTER TABLE calls in try/catch to prevent race-condition errors
  on concurrent first requests
- Wiki: Android-Kiosk v1.5.0 → v1.6.0, Step 5 rewritten (BLE scan,
  no external APK), removed gateway troubleshooting section
- Wiki: Scale-Gateway promoted to deprecated with redirect banner
- Wiki: Home What's New updated to v1.7.12 / v1.7.13
- Wiki: Features.md, kiosk README Italian UI strings translated
- .github: add bug_report.yml, feature_request.yml issue templates,
  config.yml (blank issues off, links to FAQ/Discussions/Security),
  PULL_REQUEST_TEMPLATE.md with checklist
- .github: FUNDING.yml (Ko-fi), dependabot.yml (monthly action updates)
- .github/workflows/security.yml: Trivy docker + fs scan, SARIF upload
- .github/workflows/build-scale-gateway.yml: disabled (deprecated)
- SECURITY.md: responsible disclosure policy, supported versions, scope
- CODE_OF_CONDUCT.md: Contributor Covenant 2.1
- Settings UI: About section with version display, Report Bug button,
  Changelog and GitHub links; reportBugManual() + _loadAboutSection()
- Translations: added 'about' key group (9 keys × 3 languages)

api/database.php

@@ -95,6 +95,7 @@ function initializeDB(PDO $db): void {
             quantity REAL NOT NULL,
             location TEXT NOT NULL DEFAULT 'dispensa',
             notes TEXT DEFAULT '',
+            undone INTEGER DEFAULT 0,
             created_at DATETIME DEFAULT CURRENT_TIMESTAMP,
             FOREIGN KEY (product_id) REFERENCES products(id) ON DELETE CASCADE
         );
@@ -117,10 +118,12 @@ function migrateDB(PDO $db): void {
     $cols = $db->query("PRAGMA table_info(products)")->fetchAll();
     $colNames = array_column($cols, 'name');
     if (!in_array('package_unit', $colNames)) {
-        $db->exec("ALTER TABLE products ADD COLUMN package_unit TEXT DEFAULT ''");
+        try { $db->exec("ALTER TABLE products ADD COLUMN package_unit TEXT DEFAULT ''"); }
+        catch (PDOException $e) { if (strpos($e->getMessage(), 'duplicate column') === false) throw $e; }
     }
     if (!in_array('shopping_name', $colNames)) {
-        $db->exec("ALTER TABLE products ADD COLUMN shopping_name TEXT DEFAULT ''");
+        try { $db->exec("ALTER TABLE products ADD COLUMN shopping_name TEXT DEFAULT ''"); }
+        catch (PDOException $e) { if (strpos($e->getMessage(), 'duplicate column') === false) throw $e; }
     }
 
     // Migrate transactions CHECK constraint to allow 'waste' type