feat: Complete backend and docs rebrand from Patherly to ResolutionFlow

Update APP_NAME, OpenAPI metadata, log messages, root endpoint response,
model docstrings, seed script comments, README heading, and CLAUDE.md
branding references. Frontend rebrand was completed in PR #26; this
covers everything else.

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

backend/app/core/config.py

@@ -5,7 +5,7 @@ from typing import Optional
 
 class Settings(BaseSettings):
     # Application
-    APP_NAME: str = "Patherly"
+    APP_NAME: str = "ResolutionFlow"
     DEBUG: bool = False
     API_V1_PREFIX: str = "/api/v1"