[Optimization][DataProcessor] Refactor duplicated validation logic in VL processors and serving classes

[Copilot]

Motivation

Consolidate ~200 lines of duplicated validation logic across 8 VL processor implementations and multiple serving classes. Single point of maintenance for common validation patterns.

Modifications

Multimodal validation consolidation:

• Extracted check_mm_limits() utility in fastdeploy/input/utils.py
• Supports both in (list membership) and eq (equality) type checking modes
• Added input validation for type_check_mode parameter
• Applied across all VL processors (qwen, qwen3, ernie4.5, paddleocr) in v0 and v1

Serving master check consolidation:

• Created MasterCheckMixin in fastdeploy/entrypoints/openai/utils.py
• Applied to OpenAIServingChat and OpenAIServingCompletion
• Left serving_engine and serving_models unchanged (different implementation patterns)

Impact:

• 12 files modified: +98 lines, -175 lines (net -77)
• Maintains backward compatibility
• Existing test interfaces unchanged

Usage or Command

No API changes. Refactoring maintains existing behavior.

Accuracy Tests

Not applicable - pure refactoring with no functional changes.

Checklist

• Add at least a tag in the PR title.
• Format your code, run pre-commit before commit.
• Add unit tests. Reason: Existing unit tests cover the refactored methods; test interfaces remain unchanged.
• Provide accuracy results. Reason: No functional changes to model outputs.
• If the current PR is submitting to the release branch, make sure the PR has been submitted to the develop branch, then cherry-pick it to the release branch with the [Cherry-Pick] PR tag.

Original prompt

Find and refactor duplicated code.

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