fix: simplify Dockerfile, remove duplicate branch-explorer, fix port

add banner experiments, improve notion import

fix: Permissions for runtime Notion import

fix: Replace Figure with Image component in Notion importer

debug: Add file checks before build

feat: Move Notion import to runtime (container startup)

debug: Add debug output to check if ENV vars are set

fix: Convert ARG to ENV for Notion variables in Dockerfile

feat: Add Notion import support via NOTION_PAGE_ID env var