CR-036: Add model manifest runtime warning report

[coreytshaffer]

CR-036: Model Manifest Runtime Warning Gate

Status

Implemented

Scope

Add a warning-only comparison layer between route metadata and a validated model
route manifest.

This change:

• adds a pure compare_route_to_manifest(route_payload, manifest) function
• returns a metadata-only ManifestRouteWarningReport
• warns when selected backend, selected model, or selected route metadata does
  not match the manifest
• warns when the manifest uses alias-only model identity
• warns when manifest integrity status is incomplete
• adds focused unit tests

Non-Scope

• Do not block routing.
• Do not wire this into runtime execution yet.
• Do not probe Ollama, LM Studio, Qwen Cloud, local files, or model artifacts.
• Do not hash model files.
• Do not expand signing.
• Do not mutate the ledger schema.

Acceptance Criteria

• Add a pure function that compares route metadata to a validated manifest.
• Matching route/backend/model metadata produces no warnings.
• Backend mismatch produces a warning.
• Model mismatch or alias-only identity produces a warning.
• Incomplete manifest integrity status produces a warning.
• Warning report contains only metadata, no raw prompt/data.
• Add focused unit tests.
• No runtime blocking behavior.

Validation

python -m py_compile triage_core\model_manifest.py
python -m pytest tests\test_model_manifest.py -q
python -m pytest -q
git diff --check
git status --short