Reduce duplication across assets module

- Extract validate_blake3_hash() into helpers.py, used by upload, schemas, routes
- Extract get_reference_with_owner_check() into queries, used by 4 service functions
- Extract build_prefix_like_conditions() into queries/common.py, used by 3 queries
- Replace 3 inlined tag queries with get_reference_tags() calls
- Consolidate AddTagsDict/RemoveTagsDict TypedDicts into AddTagsResult/RemoveTagsResult
  dataclasses, eliminating manual field copying in tagging.py
- Make iter_row_chunks delegate to iter_chunks
- Inline trivial compute_filename_for_reference wrapper (unused session param)
- Remove mark_assets_missing_outside_prefixes pass-through in bulk_ingest.py
- Clean up unused imports (os, time, dependencies_available)
- Disable assets routes on DB init failure in main.py

Amp-Thread-ID: https://ampcode.com/threads/T-019cb649-dd4e-71ff-9a0e-ae517365207b
Co-authored-by: Amp <amp@ampcode.com>

main.py

@@ -7,6 +7,7 @@ import folder_paths
 import time
 from comfy.cli_args import args, enables_dynamic_vram
 from app.logger import setup_logger
+from app.assets.api.routes import disable_assets_routes
 from app.assets.seeder import asset_seeder
 import itertools
 import utils.extra_config
@@ -364,6 +365,9 @@ def setup_database():
                     logging.info("Background asset scan initiated for models, input, output")
     except Exception as e:
         logging.error(f"Failed to initialize database. Please ensure you have installed the latest requirements. If the error persists, please report this as in future the database will be required: {e}")
+        if args.enable_assets:
+            disable_assets_routes()
+            asset_seeder.disable()
 
 
 def start_comfyui(asyncio_loop=None):