fix: strip duplicate inline class definitions from db shim files

models.py and repository.py are backwards-compat re-export shims from
Phase 1. Both files still contained the original 1466/1547 line class
definitions below the re-export block. These inline definitions shadowed
the correctly-imported sub-module versions and failed at import time
because Column, AuditResultEnum, etc. were no longer in scope.

Fix:
- models.py: remove all duplicate Base-subclass definitions (lines 209-
  1581). Retain EvidenceConfidenceEnum and EvidenceTruthStatusEnum (unique
  to this shim, not yet extracted to a sub-module) and the two models that
  have no sub-module yet: LLMGenerationAuditDB and AssertionDB. Add back
  the SQLAlchemy column-type imports those two models need.
- repository.py: remove all duplicate Repository class definitions (lines
  40-1692). All classes are now fully provided by the sub-repositories.

Result: 172 pytest tests pass, import OK.

dsms-gateway/Dockerfile

@@ -14,7 +14,7 @@ COPY requirements.txt .
 RUN pip install --no-cache-dir -r requirements.txt
 
 # Copy application
-COPY . .
+COPY main.py .
 
 # Environment variables
 ENV IPFS_API_URL=http://dsms-node:5001