✨[Feat] Sprint 13 Image Resize

[maruson08]

Summary

• add a production Image Resize workflow for JPEG, PNG, and WebP
• support pixel bounding dimensions, per-source percentage scaling, width-only and height-only sizing, and independent unlocked dimensions
• preserve aspect ratio by default and disable enlargement by default
• support Original, JPEG, PNG, and WebP output with JPEG/WebP quality controls and deterministic white JPEG transparency
• resize batches sequentially and package multiple results as resized_images.zip

Resource protection

• retain the existing 50 MiB file, 100-file, 500 MiB queue, 16,384-dimension, and 50-megapixel per-image limits
• enforce a 200-megapixel aggregate output-work limit
• release decoded sources and reset canvases after each item and recoverable failure

Shared architecture

• share concrete format, quality, canvas encoding, Unicode-safe naming, collision, and ZIP packaging helpers with Image Converter
• preserve orientation-aware decoding and Converter behavior

Privacy, localization, and accessibility

• processing remains browser-local with strict CSP, no runtime CDN, external fonts, analytics, telemetry, or network APIs
• add complete English, Korean, Japanese, Spanish, German, and French copy with key/placeholder parity
• provide labeled controls, keyboard-accessible input, live status/progress, responsive narrow-layout contracts, and visible locked-dimension synchronization

Validation

• node tests/run-all.mjs passes, including Image Resize, Image Converter, every PDF regression, i18n, accessibility/responsive, security, CSP, and network audits
• git diff --check passes
• bounded browser QA was attempted, but the known Windows browser bridge ACL failure occurred before rendering; no visual QA claim is made

Deferred

• crop/fit modes, compression targets, filters, rotation, metadata editing, AI upscaling, and new formats remain out of scope

This PR targets v2, not main. main remains unchanged.