Replace video_warning with target_type + has_videos/has_photos

Major template system improvements:
- Remove video_warning field from TemplateConfig model
- Add target_type, has_videos, has_photos to template context
- Templates use {% if target_type == "telegram" and has_videos %}
  for conditional Telegram warnings instead of a separate field
- date_format moved from "Telegram" to "Settings" group
- Add target type selector (Telegram/Webhook) in template editor
  to preview how templates render for each target type
- All template slots now use JinjaEditor (not plain <input>)
- Preview endpoint accepts target_type parameter
- Clean up TemplateConfigCreate schema (remove stale fields)

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

packages/server/src/immich_watcher_server/api/template_configs.py

@@ -67,7 +67,9 @@ _SAMPLE_CONTEXT = {
     "removed_assets": ["asset-id-1", "asset-id-2"],
     "people": ["Alice", "Bob"],
     "shared": True,
-    "video_warning": "⚠️ Note: Videos may not be sent due to Telegram's 50 MB file size limit.",
+    "target_type": "telegram",
+    "has_videos": True,
+    "has_photos": True,
     # Rename fields (always present, empty for non-rename events)
     "old_name": "Old Album",
     "new_name": "New Album",
@@ -82,27 +84,16 @@ _SAMPLE_CONTEXT = {
 
 class TemplateConfigCreate(BaseModel):
     name: str
+    description: str | None = None
+    icon: str | None = None
     message_assets_added: str | None = None
     message_assets_removed: str | None = None
     message_album_renamed: str | None = None
     message_album_deleted: str | None = None
-    message_asset_image: str | None = None
-    message_asset_video: str | None = None
-    message_assets_format: str | None = None
-    message_assets_more: str | None = None
-    message_people_format: str | None = None
-    date_format: str | None = None
-    common_date_template: str | None = None
-    date_if_unique_template: str | None = None
-    location_format: str | None = None
-    common_location_template: str | None = None
-    location_if_unique_template: str | None = None
-    favorite_indicator: str | None = None
     periodic_summary_message: str | None = None
-    periodic_album_template: str | None = None
     scheduled_assets_message: str | None = None
     memory_mode_message: str | None = None
-    video_warning: str | None = None
+    date_format: str | None = None
 
 
 TemplateConfigUpdate = TemplateConfigCreate  # Same shape, all optional
@@ -203,6 +194,7 @@ async def preview_config(
 
 class PreviewRequest(BaseModel):
     template: str
+    target_type: str = "telegram"  # "telegram" or "webhook"
 
 
 @router.post("/preview-raw")
@@ -229,9 +221,10 @@ async def preview_raw(
 
     # Pass 2: render with strict undefined to catch unknown variables
     try:
+        ctx = {**_SAMPLE_CONTEXT, "target_type": body.target_type}
         strict_env = SandboxedEnvironment(autoescape=False, undefined=StrictUndefined)
         tmpl = strict_env.from_string(body.template)
-        rendered = tmpl.render(**_SAMPLE_CONTEXT)
+        rendered = tmpl.render(**ctx)
         return {"rendered": rendered}
     except UndefinedError as e:
         # Still a valid template syntactically, but references unknown variable