docs(keyboard): add Keychron K15 Pro keymap documentation

Add keyboard documentation including README and JSON keymap exports
from the K15 Pro. Useful for reference when reconfiguring via
launcher.keychron.com or troubleshooting firmware issues.

docs/keyboard/README.md

@@ -0,0 +1,30 @@
+# Keychron K15 Pro Keymaps
+
+Keymap exports from [launcher.keychron.com](https://launcher.keychron.com) (Chrome, wired USB).
+Load via: Keymap → Import.
+
+See project memory for setup/udev notes.
+
+## Keymap history
+
+### `Keymap-K15 Pro RGB-20-8-33.json` — current
+- `fn+7` → Print Screen (screenshot)
+- `fn+Enter` → `\+Enter` (Claude Code soft newline)
+- `fn+;` → `\+Enter` (Claude Code soft newline — easier reach than Enter)
+- `fn+hjkl` → arrow keys (vim directions)
+- `fn+g` → LCmd / Super (Hyprland modifier — more comfortable than physical Super keys)
+
+### `Keymap-K15 Pro RGB-20-8-9.json` — superseded
+- `fn+7` → Print Screen (screenshot)
+- `fn+Enter` → `\+Enter` (Claude Code soft newline)
+- `fn+;` → `\+Enter` (Claude Code soft newline — easier reach than Enter)
+- `fn+hjkl` → arrow keys (vim directions)
+
+### `Keymap-K15 Pro RGB-20-7-41.json` — superseded
+- `fn+7` → Print Screen (screenshot)
+- `fn+Enter` → `\+Enter` (Claude Code soft newline)
+- `fn+;` → `\+Enter` (Claude Code soft newline — easier reach than Enter)
+
+### `Keymap-K15 Pro RGB-20-7-32.json` — superseded
+- `fn+7` → Print Screen (screenshot)
+- `fn+Enter` → `\+Enter` (Claude Code soft newline)