feat: Add Authorization Token support

[daniel-hayes]

Overview

Adds muxAuthorizationToken as an alternative to the muxTokenId/muxTokenSecret pair for Mux API authentication.

What was changed

• Added muxAuthorizationToken field to WorkflowCredentials interface
• Updated credential resolution to accept either token pair OR authorization token
• Removed unused context parameter from signUrl() and updated all call sites

Suggested review order

1. src/types.ts - New muxAuthorizationToken field in WorkflowCredentials
2. src/lib/workflow-credentials.ts - Resolution logic allowing auth token as alternative
3. src/lib/url-signing.ts - Removed unused context parameter from signUrl()
4. Call site updates: storyboards.ts, thumbnails.ts, transcripts.ts, moderation.ts, translate-audio.ts
5. tests/integration/signed-playback.test.ts - Updated test calls

[snyk-io]

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[daniel-hayes]

purposely didn't update the error message below so we're not encouraging our users to utilize the authorizationToken.

[walkerfrankenberg]

not super familiar with mux node, but looks like all we need to do is pass the auth token along, so lgtm

[monsieurBoutte]

LGTM