[srikar-naidu]

Description

Fixed local image uploads so they no longer create unusably large API URLs. Download PNG now converts the browser-rendered preview SVG directly to a PNG when a local image is used. Copy Image URL and Copy Meta Tags show a warning instead of copying URLs containing base64 image data.

Closes #324

How I Tested This

• Ran npm run check — passed with 0 errors.
• Ran focused export utility tests — 2 passed.
• Ran npm run test — 1226 tests passed; one unrelated existing agenda.test.ts timeout occurred.
• Verified local image detection and shareable URL warnings.
• Tested the editor export flow locally with npm run dev.

AI Assistance

AI was used for implementation guidance, code changes, testing, and debugging.

Type of Change

• Bug fix
• New template
• New feature
• Documentation
• Tests
• Refactoring
• Performance improvement
• Other

Screenshots

Not applicable. This fix changes export and copy behavior rather than the visual template layout.

Checklist

• This PR targets dev
• I was assigned the linked issue
• npm run check passes
• npm run test passes
• For a bug fix: the new test fails without my change
• Tested locally with npm run dev
• Screenshots included for visual changes
• New templates follow the [Template Guidelines](https://github.com/codercops/ogcops/blob/dev/CONTRIBUTING.md#template-guidelines)