[Owen-Liuyuxuan]

Summary

• Persist the original TensorRT/ONNX model load exception on inference_status and republish it every planning tick instead of overwriting with "Model not loaded".
• Add backend, model_type, model_loaded, and resolved model path key-values to inference_status for easier triage in Foxglove and /diagnostics.
• Refactor load/publish paths through fill_model_key_values() and publish_inference_status() so DiagnosticsInterface::clear() does not drop key-values unexpectedly.

Ported from tier4/autoware_universe#3391 (diffusion planner scope only; no ml_planner or trajectory_processor changes).

Test plan

• colcon build --packages-select autoware_diffusion_planner
• Launch with invalid/missing model paths and confirm inference_status ERROR message shows the load exception text (not only "Model not loaded")
• Successful load: inference_status OK with model path key-values on timer ticks

Made with Cursor

[github-actions]

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[SakodaShintaro]

I conformed that psim normally works.

[codecov]

Codecov Report

❌ Patch coverage is 0% with 35 lines in your changes missing coverage. Please review.
✅ Project coverage is 20.67%. Comparing base (a79d071) to head (b9223cb).

Files with missing lines	Patch %	Lines
...e_diffusion_planner/src/diffusion_planner_node.cpp	0.00%	35 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main   #13388      +/-   ##
==========================================
- Coverage   20.67%   20.67%   -0.01%     
==========================================
  Files        1951     1951              
  Lines      137663   137688      +25     
  Branches    49703    49723      +20     
==========================================
  Hits        28466    28466              
- Misses      86246    86270      +24     
- Partials    22951    22952       +1     

Flag	Coverage Δ		*Carryforward flag
full-suite	20.67% <ø> (+<0.01%)	⬆️	Carriedforward from a79d071

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