feat: support text prompt pass through

[drduhe]

Issue #, if available: n/a

Notes

Summary

• Adds text prompt passthrough support for text-prompted models (e.g., SAM3) by forwarding a user-provided prompt into the image processing request.
• Improves Image Request UX with descriptive help text across request fields.
• Updates tooling/deps to resolve npm audit issues and keep Electron packaging working.

What changed

• Text prompt passthrough
  • UI: adds a “Text Prompt” input in src/components/modal/ImageRequestModal.tsx and passes it into the request flow.
  • Request payload: extends ImageRequest with optional imageProcessorParameters and, when provided, sets CustomAttributes: text_prompt=<urlencoded> in src/util/mrHelper.ts.
• Better request form guidance
  • Adds per-field descriptions for Bucket/Image/Model/Outputs/Tiling/Feature distillation/ROI/etc. in ImageRequestModal.tsx.
• Extents calculation robustness
  • scripts/calculate_extents.py now falls back to GCP-based extents when a dataset has a default/empty geotransform (improves handling of imagery lacking a proper geotransform).
• Dependency/security/tooling
  • Upgrades electron-builder to ^26.5.0 and refreshes multiple deps in package.json / package-lock.json.
  • Adds patch-package + postinstall and introduces patches/@electron+rebuild+4.0.1.patch to keep Electron rebuild compatible with tar@7 (ESM import fix).
  • Updates .pre-commit-config.yaml to exclude patches/** from copyright hooks (patch files are generated and headers can break patch application).

Testing

• npm audit now reports 0 vulnerabilities.
• npm run build succeeds (tsc + vite + electron-builder).

Notes / follow-ups

• Patch files in patches/ should be tracked in git so CI/dev installs apply them consistently.
• Electron packaging still emits expected warnings (icon not set, notarization skipped, Node deprecation warnings); these are non-blocking.

Checklist

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• Code changes are compact and well-structured to facilitate easy review
• Changes are documented in the README.md and other relevant documentation pages
• PR title and description accurately reflect the changes and are detailed enough for historical tracking
• PR contains tests that cover all new code and the code has been manual tested
• All new dependencies are declared (if any), and no unnecessary libraries are added
• Performance impacts (if any) of the changes are evaluated and documented
• Security implications of the changes (if any) are reviewed and addressed
• I have read the Contributing Guidelines and agree to follow the Code of Conduct

By submitting this pull request, I confirm that you can use, modify, copy, and redistribute this contribution, under the terms of your choice.

[devinglauner]

LGTM