fix: Replace bash4-only lowercase expansion with bash3.2 compatible tr

[Rusty-Alucard]

Problem

lib/cli_adapter.sh uses the ${var,,} lowercase expansion syntax which is a bash 4.0+ feature. This causes a bad substitution error on macOS, where the system /bin/bash is version 3.2.

lib/cli_adapter.sh: line 29: cli_type=${cli_type,,}: bad substitution

Fix

Replace ${cli_type,,} with a POSIX-compatible tr pipeline:

# Before (bash 4+ only)
cli_type="${cli_type,,}"

# After (bash 3.2 compatible)
cli_type="$(echo "$cli_type" | tr '[:upper:]' '[:lower:]')"

Compatibility

• ✅ bash 3.2 (macOS default /bin/bash)
• ✅ bash 4.x
• ✅ bash 5.x
• ✅ POSIX-compliant (uses tr which is universally available)

Testing

The tr '[:upper:]' '[:lower:]' approach correctly lowercases strings on both bash 3.2 and bash 4+, and handles all the alias cases (gemini, agy → antigravity) that the _cli_adapter_normalize_cli_type function is designed for.