[Optimization] Deduplicate shared image/video utilities across VL processors

[luukunn]

Motivation

• Extract shared image utility functions (smart_resize, round/ceil/floor_by_factor, is_scaled_image) into fastdeploy/input/image_processors/common.py, covering both qwen and paddleocr variants
• Extract shared video utilities (VideoReaderWrapper, read_video_decord, sample_frames) into fastdeploy/input/video_utils.py, with separate sample_frames_qwen and sample_frames_paddleocr variants
• Update all 4 VL image_processor.py files to import from the new shared modules instead of maintaining local copies
• Update qwen_vl, qwen3_vl, paddleocr_vl processor files to use sample_frames from video_utils.py; remove now-empty qwen_vl_processor/process_video.py and paddleocr_vl_processor/process_video.py

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💡 如若此PR是Cherry Pick，PR标题需遵循格式，在最开始加上[Cherry-Pick]标签，以及最后面加上原PR ID，例如[Cherry-Pick][CI] Add check trigger and logic(#5191)

Modifications

Usage or Command

Accuracy Tests

Checklist

• Add at least a tag in the PR title.
  • Tag list: [[FDConfig],[APIServer],[Engine], [Scheduler], [PD Disaggregation], [Executor], [Graph Optimization], [Speculative Decoding], [RL], [Models], [Quantization], [Loader], [OP], [KVCache], [DataProcessor], [BugFix], [Docs], [CI], [Optimization], [Feature], [Benchmark], [Others], [XPU], [HPU], [GCU], [DCU], [Iluvatar], [Metax]]
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• Add unit tests. Please write the reason in this PR if no unit tests.
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[paddle-bot]

Thanks for your contribution!

[codecov-commenter]

Codecov Report

❌ Patch coverage is 82.52427% with 36 lines in your changes missing coverage. Please review.
⚠️ Please upload report for BASE (develop@aee293b). Learn more about missing BASE report.

Files with missing lines	Patch %	Lines
fastdeploy/input/video_utils.py	79.38%	20 Missing and 7 partials ⚠️
fastdeploy/input/image_processors/common.py	85.71%	5 Missing and 4 partials ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             develop    #6988   +/-   ##
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  Coverage           ?   73.28%           
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  Files              ?      399           
  Lines              ?    56041           
  Branches           ?     8842           
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  Hits               ?    41069           
  Misses             ?    12071           
  Partials           ?     2901           

Flag	Coverage Δ
GPU	73.28% <82.52%> (?)

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