feat: add feed-specific follow list activation

- Add new SQL functions for feed-specific follow list management:
  - get_feed_follow_lists: get follow lists assigned to a feed
  - get_available_follow_lists: get all available lists (own + others)
  - assign_follow_list_to_feed: assign any follow list to a feed
  - unassign_follow_list_from_feed: remove follow list from feed
  - activate_follow_list_for_all_feeds: bulk activate for all user feeds
  - deactivate_follow_list_from_all_feeds: bulk deactivate

- Create PvFeedFollowLists component for managing follow lists per feed
  - Similar to PvFeedManagement pattern for generators
  - Shows creator username for lists from other users
  - Add/remove follow lists from feed

- Update PvFollowListManager to be feed-aware:
  - Read feedId from page client state
  - Pass feedId to API calls
  - Add menu with "Activate for all feeds" and "Deactivate from all feeds"

- Update API client with new methods and feedId parameters

Closes #143