Add Magic Hour to ecosystem

[runshouse]

Summary

Adds Magic Hour to the multimodal API ecosystem with its official homepage and public API documentation.

Validation

• YAML parses successfully
• magic-hour slug is unique
• Description is within 120 characters
• Tag count is within the six-tag limit
• git diff --check passes

The repository validator could not run locally because PyYAML is not installed; CI can run the publisher's canonical validation.

Disclosure: I am affiliated with Magic Hour.