Add Titan embeddings support to the Bedrock bridge

[jaksa-v]

Summary

• add Bedrock-specific embeddings request mapping for the Laravel AI bridge
• pass Titan V2 embedding dimensions and options through to Prism
• bump the Bedrock Prism dependency to clinically/prism-bedrock ^0.1.2

Why

Once Titan embeddings support exists in clinically/prism-bedrock, this bridge still needs to map Laravel AI embedding requests onto the Bedrock-specific provider options that Titan expects. Without that step, dimensions() and related Bedrock embeddings options never reach the underlying request.

What changed

• Added Bedrock-specific embedding option mapping in BedrockProvider.
• Overrode Bedrock embeddings generation in BedrockPrismGateway so provider options are passed through correctly.
• Added package config for Bedrock embeddings options.
• Added tests covering Titan embedding option pass-through.
• Updated the Bedrock service provider namespace in tests so the branch remains independently runnable against the current upstream baseline.
• Bumped the Bedrock Prism dependency to ^0.1.2.

Dependency

This PR depends on the Prism Titan embeddings work:

• Add Titan embeddings support prism-bedrock#2

Review note

The only overlap with #1 is the minimal Bedrock service provider namespace fix in the tests. This PR does not include the separate image-provider or provider-options merge work.

Verification

• php vendor/bin/phpunit