feat: name-based device matching and defdevice config

[malpern]

Summary

Add name-based device matching to the (device ...) switch condition and a (defdevice ...) configuration block.

Builds on the device identity pipeline from PR #5.

What this includes

1. (defdevice ...) config block — Define device aliases mapping friendly names to match criteria (device name substrings, vendor/product IDs, etc.)
2. (device "Kinesis") string matching — Match devices by name string in switch conditions instead of fragile numeric indices
3. Device alias resolution — Parser resolves device names at config load time against the registry

Why

Numeric device indices are assigned in registration order and aren't stable across reboots or replug events. Name-based matching is what users actually want for per-device key mappings.

Example

(defdevice kinesis "Kinesis Advantage360")
(defdevice trackpad "Apple Internal Keyboard")

(switch
  ((device kinesis) X break)
  ((device trackpad) Y break))

Dependencies

• PR feat: thread device identity for per-device switch conditions #5 (device identity pipeline)
• Stable indexing (issue TBD) would make this more robust but isn't strictly required

[malpern]

Parent feature: malpern/KeyPath#63 (per-keyboard rule targeting)