[AutoDeploy] Improved config deepmerge handling

[lucaslie]

Better handling of deepmerging nested configs/dictionaries from various config sources in the new config system.

Please check out the updated README section for more details on the next iteration of providing AutoDeploy configurability.

[Copilot]

Pull Request Overview

This PR replaces the previous Pydantic-based deep-update approach with an OmegaConf-backed deep merge utility, refactors several settings sources and factory classes to use the new helper, and expands example scripts and documentation to showcase advanced CLI and YAML configuration.

• Introduces deep_merge_dicts using OmegaConf for recursive merging.
• Refactors DynamicYamlWithDeepMergeSettingsSource and settings classes to leverage the new merge logic.
• Updates model factories, example scripts, and README with improved defaults, CLI dot notation, and YAML examples.

Reviewed Changes

Copilot reviewed 9 out of 10 changed files in this pull request and generated 3 comments.

Show a summary per file

File	Description
tensorrt_llm/_torch/auto_deploy/utils/_config.py	Added deep_merge_dicts and refactored YAML source to merge configs via OmegaConf.
tensorrt_llm/_torch/auto_deploy/models/hf.py	Reworked tokenizer/model default handling to use deep_merge_dicts.
tensorrt_llm/_torch/auto_deploy/models/factory.py	Simplified the register method signature.
tensorrt_llm/_torch/auto_deploy/llm_args.py	Migrated to Pydantic v2 settings mixin, added CLI extra-args handling.
tensorrt_llm/_torch/auto_deploy/config/default.yaml	Added placeholder default YAML config.
setup.py	Included the new YAML config files in package data.
examples/auto_deploy/build_and_run_ad.py	Updated example script to use OmegaConf merging and extended CLI features.
examples/auto_deploy/README.md	Expanded documentation with detailed CLI/YAML configuration examples.

Comments suppressed due to low confidence (1)

tensorrt_llm/_torch/auto_deploy/config/default.yaml:2

• [nitpick] The default config file is empty but the docs reference default transform settings. Consider populating this file with the baseline defaults or clarifying that no defaults are needed.

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