Remove unused langchain dependencies and disable element highlighting

- Remove langchain-astradb and langchain-mongodb from dependencies
- Set highlight_elements to False in browser configuration

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

Remove redundant client.close() in website API skills

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

Merge pull request #161 from vibesurf-ai/sim

Sim

Merge pull request #156 from vibesurf-ai/sim

Sim

Merge pull request #155 from vibesurf-ai/sim

Optimize dependencies and clean up unused components

Merge pull request #154 from vibesurf-ai/sim

Sim

Merge pull request #151 from vibesurf-ai/im

Force is_default=True when no default profile exists

Merge pull request #149 from vibesurf-ai/im

Im

Merge pull request #147 from vibesurf-ai/bu

Bu

Merge pull request #146 from vibesurf-ai/bu

Update README video section with YouTube tutorial link