[BUG/FEATURE] Robust i2v and i2i support via "API-via-Browser" Bypass

Description:
Character consistency in v0.7.0 is currently blocked because i2v and i2i require an image upload. The current transport logic falls back to a legacy HTTP POST which fails with 401 Unauthorized.

Empirical research using browser-harness has identified a highly robust "API-via-Browser" bypass that eliminates the need for complex UI clicking and solves the auth issue.

Technical Discovery:

• Hidden Gateway: Google Flow maintains a persistent hidden file input: input[type="file"][accept="image/*"].
• Direct Upload: Verified that calling page.set_input_files(selector, path) on this input automatically triggers the uploadImage XHR request without any button clicking.
• UUID Extraction: The image UUID (needed for generation) is returned in the JSON response at media.name.
• Auth Solution: By using page.evaluate(fetch, ...) inside the browser session, we can reuse the application's internal Authorization (Bearer) tokens and session state.

Proposed Implementation (Task 0 Fix):

1. Implement upload_image in ui_automation.py:

   • Use page.set_input_files('input[type="file"][accept="image/*"]', path).
   • Register a page.on("response") listener to capture the result from https://aisandbox-pa.googleapis.com/v1/flow/uploadImage.
   • Return the extracted media[0].name.

2. Implement i2v (Image-to-Video) in ui_automation_video.py:

   • Instead of navigating dropdowns, capture the Authorization header from the upload request.
   • Use page.evaluate() to call the batchAsyncGenerateVideoStartAndEndImage endpoint using fetch().
   • This ensures all cookies and tokens are valid, bypassing the 401 error.

Impact:

• Restores character consistency for automated pipelines (Stickman/Kitten archetypes).
• significantly faster than UI-automation based clicking.
• Robust against UI layout changes.

Verification:

• Verified manually using a standalone script that successfully triggered the upload and captured the UUID.
• Requires integration into the UiAutomationTransport protocol.