Add in-app help page with user manual (Romanian)

Adds a /help page served from the dashboard navigation, containing the full
Romanian user manual for operators: dashboard, playlist management, adding
media, removing files from playlists, player management, and the advanced
edited-media view.

Implementation notes
- Manual is pre-rendered to HTML with pandoc and shipped as a static asset
  (app/static/help/_manual_body.html) rather than parsed at runtime. This
  keeps the container free of a Markdown dependency and makes the page render
  identically regardless of what is installed.
- /help is login-protected; the sidebar table of contents is derived from the
  level-2 headings at request time.
- Screenshots are served from app/static/help/screenshots/ (32 images).
- Regenerate after editing the manual:
    documentatie/convert_help_page.sh
    docker compose up -d --build

Also adds
- backup_players_playlists.sh / restore_database.sh for DB backup and restore.
- .gitignore rules so local database backups (real production data), generated
  .docx files and duplicate screenshot copies are never committed.

documentatie/convert_manual.sh

@@ -0,0 +1,84 @@
+#!/bin/bash
+# ============================================================================
+# convert_manual.sh - Converteste manualul DigiServer in format DOCX
+# ----------------------------------------------------------------------------
+# Genereaza un document Word cu:
+#   - Cuprins automat
+#   - Secțiuni numerotate
+#   - Capturi de ecran incluse (din folderul screenshots/)
+#
+# Utilizare:
+#   ./convert_manual.sh
+# ============================================================================
+set -e
+
+cd "$(dirname "$0")"
+
+echo "============================================================"
+echo " Conversie Manual DigiServer -> DOCX"
+echo "============================================================"
+echo
+
+# ---------------------------------------------------------------------------
+# Verificare Pandoc
+# ---------------------------------------------------------------------------
+if ! command -v pandoc &> /dev/null; then
+    echo "✗ Pandoc nu este instalat."
+    echo
+    echo "  Instalati cu:"
+    echo "    sudo apt-get update && sudo apt-get install -y pandoc"
+    echo
+    exit 1
+fi
+
+echo "✓ Pandoc detectat: $(pandoc --version | head -1)"
+echo
+
+# ---------------------------------------------------------------------------
+# Verificare fisiere sursa
+# ---------------------------------------------------------------------------
+if [ ! -f "Manual-Utilizare-DigiServer.md" ]; then
+    echo "✗ Fisierul Manual-Utilizare-DigiServer.md nu a fost gasit."
+    exit 1
+fi
+echo "✓ Manual gasit"
+
+mkdir -p screenshots
+SCREENSHOT_COUNT=$(ls -1 screenshots/*.png screenshots/*.jpg 2>/dev/null | wc -l)
+echo "✓ Capturi de ecran disponibile: $SCREENSHOT_COUNT"
+if [ "$SCREENSHOT_COUNT" -eq 0 ]; then
+    echo "  (Nu exista capturi - documentul va fi generat doar cu text)"
+fi
+echo
+
+# ---------------------------------------------------------------------------
+# Conversie
+# ---------------------------------------------------------------------------
+echo "Conversie in curs..."
+echo
+
+pandoc Manual-Utilizare-DigiServer.md \
+  --toc \
+  --toc-depth=2 \
+  --number-sections \
+  --resource-path=screenshots \
+  --metadata title="Manual de Utilizare – DigiServer v2" \
+  --metadata lang="ro-RO" \
+  -o Manual-Utilizare-DigiServer.docx
+
+# ---------------------------------------------------------------------------
+# Verificare rezultat
+# ---------------------------------------------------------------------------
+echo
+if [ -f "Manual-Utilizare-DigiServer.docx" ]; then
+    echo "============================================================"
+    echo " ✓ Document creat cu succes!"
+    echo "============================================================"
+    ls -lh Manual-Utilizare-DigiServer.docx
+    echo
+    echo "Deschideti cu:  libreoffice Manual-Utilizare-DigiServer.docx"
+    echo "            sau deschideti in Microsoft Word."
+else
+    echo "✗ Eroare: documentul nu a fost creat."
+    exit 1
+fi