docs: update repository boundaries and Agent Canvas architecture - #688

Verified update permissions
Fetching and validating config file...
Fetching .mintignore file...
Fetching ASSISTANT.md file...
Discovering assistant skills...
Successfully validated docs.json
No .mintignore file found
No Assistant.md file found
No assistant skills found
Only runtime docsConfig fields changed, partial deployment update
Runtime-only docsConfig changes, partial deployment update
file too large - skipping: openhands/static/img/teaser.mp4
Fetched all file paths
Fetched 2 OpenApi file(s):
  - openapi/V0_openapi.json
  - openapi/agent-sdk.json
Fetched 0 AsyncApi file(s)
Generated OpenAPI pages for navigation
Skipped AsyncAPI navigation generation
No SDK reference pages configured
No GraphQL reference pages configured
No GraphQL deployment changes required
Persisted 87 generated API page(s)
No GraphQL deployment changes required
Successfully updated API reference metadata.
No stale files found
Updating targeted paths:
  openhands/usage/agent-canvas/architecture.mdx
  openhands/usage/agent-canvas/backends.mdx
  openhands/usage/agent-canvas/setup.mdx
  overview/introduction.mdx
Successfully updated deployment
No LaTeX detected
Successfully saved config
No stale tracked assets found
Updating navigation...
Navigation updated
Skipped editor nav regeneration (no existing record)
Queued search indexing
Skipped search indexing (non-manual update).
Successfully deleted stale OpenAPI document(s)
Successfully deleted stale AsyncAPI document(s)
Successfully deleted stale tracked asset(s)
Contextual starter questions are not enabled.
Starting page revalidation...
Revalidating all pages...
Revalidating 398 paths
Page revalidation complete
Queued update of llms-full.txt
Skipping revalidation
Updated deployment cache
Skipped post-activation contextual starter questions.
Skipped post-activation search indexing
Skipped post-activation search indexing.
Skipped post-activation page revalidation
Skipped post-activation update of llms-full.txt