fix(spawn): case-insensitive model-glob matching for agent/session spawns

[Brian Krabach (bkrabach)]

Summary

• Agent/session spawn operations now use case-insensitive model-glob matching, consistent with the routing matrix
• Spawned child sessions inherit the routing hook config (custom_routing_dirs) so custom user matrices reach spawned agents

Technical Details

Bug: spawn_utils model resolution was OS-dependent

• spawn_utils used raw fnmatch.filter() for model-hint resolution
• This is OS-dependent: case-sensitive on Linux, case-insensitive on Windows
• Caused mixed-case model ids (e.g., Qwen3.6-..., Claude3...) to silently fail to match globs

Fix

• Now lowercases both sides: fnmatch.filter([m.lower() for m in names], pattern.lower())
• Deterministic on all platforms
• Consistent with routing matrix fix and unified-llm-client reference behavior

Config propagation to spawned sessions

• Added tests verifying custom_routing_dirs config deep-merges into spawned child sessions
• Path: compose() → merge_module_lists() → fresh mount() on child
• Fixes reach agent sub-sessions, not just the main session

Testing

uv run pytest tests/test_spawn_utils.py tests/test_bundle.py -q

All pass, including new deep-merge verification tests.

Note

This fix pairs with amplifier-bundle-routing-matrix PR #30 (custom matrix loading at runtime).

Co-authored with Amplifier