feat: Add Strands Provider for AI SDK

[epietrowicz]

Summary

• Adds a new @launchdarkly/server-ai-strands package that implements a LaunchDarkly AI provider for the AWS Strands Agents SDK
• Implements StrandsProvider integrating with the LaunchDarkly AI SDK (LDAIClient) to track token usage, latency, errors, and feedback for Strands-based AI calls
• Includes CI workflow (server-ai-strands.yml) and release-please configuration for the new package

Test plan

• Unit tests pass: yarn workspace @launchdarkly/server-ai-strands test
• Lint passes: yarn workspace @launchdarkly/server-ai-strands lint
• Build passes: yarn workspaces foreach -pR --topological-dev --from '@launchdarkly/server-ai-strands' run build
• Verify StrandsProvider correctly reports token usage, latency, and errors to LaunchDarkly

🤖 Generated with Claude Code

[jsonbailey]

Thanks for the PR. Holding off per our slack conversation until we get the rest of the base changes into the JS sdk.