F07-T04: Unit tests for alias chaining

[leocamello]

Description

Implement comprehensive unit tests for alias chaining functionality.

Tests to Add

• alias_chain_two_levels
• alias_chain_three_levels
• alias_chain_stops_at_max_depth
• alias_preserves_existing_single_level_behavior

Acceptance Criteria

• All chaining tests pass
• Existing alias tests still pass
• Edge cases covered

Files

• src/routing/mod.rs - tests module