Issue #003: File-based Storage System

[fbbp]

Description

Implement the storage abstraction layer using the file system to persist teams, tasks, and messages.

Acceptance Criteria

• Storage interface with CRUD methods
• FileStorage class implementing the interface
• Teams stored in tm_data/teams/{teamId}.json
• Inbox/outbox in tm_data/inbox/ and tm_data/outbox/
• Task pool in tm_data/tasks/pool.json
• Atomic write operations (write to temp, rename)
• File locking for concurrent access safety

Sub-issues

• Add ready-to-use configuration files with (?) placeholders #3.1 Define Storage interface
• Add ready-to-use configuration files with (?) placeholders #3.2 Implement FileStorage for teams
• Add ready-to-use configuration files with (?) placeholders #3.3 Implement FileStorage for inbox/outbox
• Add ready-to-use configuration files with (?) placeholders #3.4 Implement FileStorage for task pool
• Add ready-to-use configuration files with (?) placeholders #3.5 Add file locking and atomic writes

Dependencies

• Blocked by: #002

Priority

P0

[affaan-m]

See discussion in #122 - these issues appear to be for a separate TeammateTool project.

[affaan-m]

Closing: This is a feature request for a separate TeammateTool project, not a bug/feature for ECC. Please create these issues in your own repository. Feel free to reference ECC patterns!