Simplify templates to pure Jinja2 + CodeMirror editor + variable reference

Major template system overhaul:
- TemplateConfig simplified from 21 fields to 9: removed all sub-templates
  (asset_image, asset_video, assets_format, people_format, etc.)
  Users write full Jinja2 with {% for %}, {% if %} inline.
- Default EN/RU templates seeded on first startup (user_id=0, system-owned)
  with proper Jinja2 loops over added_assets, people, albums.
- build_full_context() simplified: passes raw data directly to Jinja2
  instead of pre-rendering sub-templates.
- CodeMirror editor for template slots (HTML syntax highlighting,
  line wrapping, dark theme support via oneDark).
- Variable reference API: GET /api/template-configs/variables returns
  per-slot variable descriptions + asset_fields for loop contexts.
- Variable reference modal in UI: click "{{ }} Variables" next to any
  slot to see available variables with Jinja2 syntax examples.
- Route ordering fix: /variables registered before /{config_id}.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

packages/server/src/immich_watcher_server/database/models.py

@@ -108,7 +108,11 @@ class TrackingConfig(SQLModel, table=True):
 
 
 class TemplateConfig(SQLModel, table=True):
-    """Message template configuration: all template slots from the blueprint."""
+    """Message template configuration with full Jinja2 templates.
+
+    Each slot is a complete Jinja2 template with access to loops, conditionals,
+    and filters. No sub-templates needed -- use {% for %}, {% if %} inline.
+    """
 
     __tablename__ = "template_config"
 
@@ -117,49 +121,19 @@ class TemplateConfig(SQLModel, table=True):
     name: str  # e.g. "Default EN", "Default RU"
     icon: str = Field(default="")
 
-    # Event messages
-    message_assets_added: str = Field(
-        default='📷 {added_count} new photo(s) added to album "{album_name}"{common_date}{common_location}.{people}{assets}{video_warning}'
-    )
-    message_assets_removed: str = Field(
-        default='🗑️ {removed_count} photo(s) removed from album "{album_name}".'
-    )
-    message_album_renamed: str = Field(
-        default='✏️ Album "{old_name}" renamed to "{new_name}".'
-    )
-    message_album_deleted: str = Field(
-        default='🗑️ Album "{album_name}" was deleted.'
-    )
+    # Event-driven notification templates (full Jinja2)
+    message_assets_added: str = Field(default="")
+    message_assets_removed: str = Field(default="")
+    message_album_renamed: str = Field(default="")
+    message_album_deleted: str = Field(default="")
 
-    # Asset item formatting
-    message_asset_image: str = Field(default="\n  • 🖼️ {filename}")
-    message_asset_video: str = Field(default="\n  • 🎬 {filename}")
-    message_assets_format: str = Field(default="\nAssets:{assets}")
-    message_assets_more: str = Field(default="\n  • ...and {more_count} more")
-    message_people_format: str = Field(default=" People: {people}.")
+    # Scheduled notification templates (full Jinja2)
+    periodic_summary_message: str = Field(default="")
+    scheduled_assets_message: str = Field(default="")
+    memory_mode_message: str = Field(default="")
 
-    # Date/location formatting
+    # Settings
     date_format: str = Field(default="%d.%m.%Y, %H:%M UTC")
-    common_date_template: str = Field(default=" from {date}")
-    date_if_unique_template: str = Field(default=" ({date})")
-    location_format: str = Field(default="{city}, {country}")
-    common_location_template: str = Field(default=" in {location}")
-    location_if_unique_template: str = Field(default=" 📍 {location}")
-    favorite_indicator: str = Field(default="❤️")
-
-    # Scheduled notification templates
-    periodic_summary_message: str = Field(
-        default="📋 Tracked Albums Summary ({album_count} albums):{albums}"
-    )
-    periodic_album_template: str = Field(
-        default="\n  • {album_name}: {album_url}"
-    )
-    scheduled_assets_message: str = Field(
-        default='📸 Here are some photos from album "{album_name}":{assets}'
-    )
-    memory_mode_message: str = Field(default="📅 On this day:{assets}")
-
-    # Telegram-specific
     video_warning: str = Field(
         default="\n\n⚠️ Note: Videos may not be sent due to Telegram's 50 MB file size limit."
     )
@@ -167,6 +141,81 @@ class TemplateConfig(SQLModel, table=True):
     created_at: datetime = Field(default_factory=_utcnow)
 
 
+# --- Default template content (EN) ---
+
+DEFAULT_TEMPLATE_EN = {
+    "message_assets_added": """📷 {{ added_count }} new photo(s) added to album "{{ album_name }}".\
+{% if people %}
+👤 {{ people | join(", ") }}{% endif %}\
+{% if added_assets %}
+{% for asset in added_assets %}\
+  • {% if asset.type == "VIDEO" %}🎬{% else %}🖼️{% endif %} {{ asset.filename }}\
+{% if asset.city %} 📍 {{ asset.city }}{% if asset.country %}, {{ asset.country }}{% endif %}{% endif %}\
+{% if asset.is_favorite %} ❤️{% endif %}
+{% endfor %}\
+{% endif %}\
+{{ video_warning }}""",
+
+    "message_assets_removed": '🗑️ {{ removed_count }} photo(s) removed from album "{{ album_name }}".',
+
+    "message_album_renamed": '✏️ Album "{{ old_name }}" renamed to "{{ new_name }}".',
+
+    "message_album_deleted": '🗑️ Album "{{ album_name }}" was deleted.',
+
+    "periodic_summary_message": """📋 Tracked Albums Summary ({{ albums | length }} albums):\
+{% for album in albums %}
+  • {{ album.name }}: {{ album.asset_count }} assets{% if album.url %} — {{ album.url }}{% endif %}\
+{% endfor %}""",
+
+    "scheduled_assets_message": """📸 Photos from "{{ album_name }}":\
+{% for asset in assets %}
+  • {% if asset.type == "VIDEO" %}🎬{% else %}🖼️{% endif %} {{ asset.filename }}\
+{% endfor %}""",
+
+    "memory_mode_message": """📅 On this day:\
+{% for asset in assets %}
+  • {% if asset.type == "VIDEO" %}🎬{% else %}🖼️{% endif %} {{ asset.filename }} ({{ asset.created_at[:4] }})\
+{% endfor %}""",
+}
+
+# --- Default template content (RU) ---
+
+DEFAULT_TEMPLATE_RU = {
+    "message_assets_added": """📷 {{ added_count }} новых фото добавлено в альбом "{{ album_name }}".\
+{% if people %}
+👤 {{ people | join(", ") }}{% endif %}\
+{% if added_assets %}
+{% for asset in added_assets %}\
+  • {% if asset.type == "VIDEO" %}🎬{% else %}🖼️{% endif %} {{ asset.filename }}\
+{% if asset.city %} 📍 {{ asset.city }}{% if asset.country %}, {{ asset.country }}{% endif %}{% endif %}\
+{% if asset.is_favorite %} ❤️{% endif %}
+{% endfor %}\
+{% endif %}\
+{{ video_warning }}""",
+
+    "message_assets_removed": '🗑️ {{ removed_count }} фото удалено из альбома "{{ album_name }}".',
+
+    "message_album_renamed": '✏️ Альбом "{{ old_name }}" переименован в "{{ new_name }}".',
+
+    "message_album_deleted": '🗑️ Альбом "{{ album_name }}" был удалён.',
+
+    "periodic_summary_message": """📋 Сводка альбомов ({{ albums | length }}):\
+{% for album in albums %}
+  • {{ album.name }}: {{ album.asset_count }} файлов{% if album.url %} — {{ album.url }}{% endif %}\
+{% endfor %}""",
+
+    "scheduled_assets_message": """📸 Фото из "{{ album_name }}":\
+{% for asset in assets %}
+  • {% if asset.type == "VIDEO" %}🎬{% else %}🖼️{% endif %} {{ asset.filename }}\
+{% endfor %}""",
+
+    "memory_mode_message": """📅 В этот день:\
+{% for asset in assets %}
+  • {% if asset.type == "VIDEO" %}🎬{% else %}🖼️{% endif %} {{ asset.filename }} ({{ asset.created_at[:4] }})\
+{% endfor %}""",
+}
+
+
 class NotificationTarget(SQLModel, table=True):
     """Notification destination with tracking and template config references."""