This refactoring improves separation of concerns by splitting a single
coauthor repository into two distinct repositories with clear responsibilities:

**TeamMemberRepo (team_member_repo.rs):**
- Manages the persistent registry of team members
- Handles CRUD operations for individual team members (add, remove, list, get)

**MobSessionRepo (mob_session_repo.rs):**
- Manages the active mob programming session state
- Handles adding/removing coauthors from the current session
- Manages the temporary list of active collaborators
- Handles clearing of mob session

**Benefits:**
- **Single Responsibility Principle**: Each repository has one clear purpose
- **Better testability**: Can mock and test each concern independently
- **Clearer API**: Method names like `team_member_repo.add()` vs `mob_repo.add_coauthor()`
  make the intent explicit
- **Reduced coupling**: Mob session management is decoupled from member management
- **Domain clarity**: Aligns code structure with the conceptual model of mob programming

**Usage Pattern:**
1. Use TeamMemberRepo to manage your team roster (persistent)
2. Use MobSessionRepo to manage who's active in the current session (temporary)

This separation makes the codebase more maintainable and the domain model
more explicit, following the principle that different lifecycle concerns
should be managed separately.

- Move mob_session_repo.rs and team_member_repo.rs to src/repositories/
- Create repositories/mod.rs with clean re-exports
- Update commands/mod.rs with clean re-exports

- Updated futures crates from 0.3.28 to 0.3.31 to fix yanked dependency
- Resolved cargo audit warning for futures-util vulnerability
- Updated 89 packages to latest compatible versions

Fixes security advisory for yanked crate in dependency tree:
futures-util 0.3.28 → 0.3.31