feat(blankpad): desk.sh profile switcher, hotplug autoswitch daemon, keybinds doc generator + bats suite

- desk.sh: list/current/switch/cycle/match/capture over cfg/desk-*.kdl
  profiles; apply = relink display.kdl, niri validate (rollback on fail),
  load-config-file, noctalia notification; match scores // requires: lines
  (EDID long names) against live niri msg outputs
- desk-autoswitch.sh: watch niri msg --json event-stream for
  OutputsChanged, debounced desk.sh match --apply, reconnect loop
- blankpad-desk-autoswitch.service: ConditionHost=blankpad user unit
- gen-keybinds.sh: keybinds.kdl -> markdown cheat sheet (sections from
  // --- headers, hotkey-overlay-title preferred over action)
- tests/: 27 bats cases, all green (desk 16, gen-keybinds 6,
  niri-config 5 incl. real niri validate on the assembled tree with
  each desk profile active)

scripts/gen-keybinds.sh

@@ -0,0 +1,81 @@
+#!/usr/bin/env bash
+# scripts/gen-keybinds.sh — generate the niri keybinding cheat sheet (markdown)
+# from a keybinds.kdl file.
+#
+# Usage:
+#   gen-keybinds.sh [keybinds.kdl]              # markdown to stdout
+#   gen-keybinds.sh [keybinds.kdl] --write OUT  # markdown to OUT
+#
+# Default input: ~/.config/niri/cfg/keybinds.kdl
+# Recognized: section comments `// ─── Name ───`, bind lines with optional
+# hotkey-overlay-title="..."; the action inside { } is used when there is no title.
+
+set -euo pipefail
+
+usage() { sed -n '2,11p' "$0" | sed 's/^# \{0,1\}//'; }
+
+KBD=""
+OUT=""
+while [ $# -gt 0 ]; do
+  case "$1" in
+    -h|--help) usage; exit 0 ;;
+    --write)   OUT="${2:?--write needs an output path}"; shift 2 ;;
+    *)         KBD="$1"; shift ;;
+  esac
+done
+KBD="${KBD:-$HOME/.config/niri/cfg/keybinds.kdl}"
+[ -f "$KBD" ] || { echo "error: no such file: $KBD" >&2; exit 1; }
+
+gen() {
+  echo "# Niri Keybindings"
+  echo
+  echo "> GENERATED by \`scripts/gen-keybinds.sh\` from \`$(basename "$KBD")\` — do not edit by hand."
+  echo
+  awk '
+    # section header: // ─── Name ───
+    /^[[:space:]]*\/\/[[:space:]]*─+ (.+) ─+[[:space:]]*$/ {
+      s = $0
+      sub(/^[[:space:]]*\/\/[[:space:]]*─+ /, "", s)
+      sub(/ ─+[[:space:]]*$/, "", s)
+      if (in_table) print ""
+      print "## " s
+      print ""
+      print "| Key | Action |"
+      print "|-----|--------|"
+      in_table = 1
+      next
+    }
+    # bind line: KEY [flags] [hotkey-overlay-title="..."] { action; }
+    /^[[:space:]]*[A-Z][A-Za-z0-9+]*( |$)/ && /\{/ {
+      key = $1
+      title = ""
+      if (match($0, /hotkey-overlay-title="[^"]*"/)) {
+        title = substr($0, RSTART + 22, RLENGTH - 23)
+      }
+      act = ""
+      if (match($0, /\{[^}]*\}/)) {
+        act = substr($0, RSTART + 1, RLENGTH - 2)
+        sub(/;[[:space:]]*$/, "", act)
+        gsub(/[[:space:]]+/, " ", act)
+        sub(/^ /, "", act); sub(/ $/, "", act)
+      }
+      out = (title != "") ? title : act
+      gsub(/\|/, "\\|", out)
+      print "| `" key "` | " out " |"
+      n++
+      next
+    }
+    END {
+      if (in_table) print ""
+      printf("<!-- %d bindings -->\n", n) > "/dev/stderr"
+    }
+  ' "$KBD"
+}
+
+if [ -n "$OUT" ]; then
+  mkdir -p "$(dirname "$OUT")"
+  gen > "$OUT"
+  echo "wrote $OUT" >&2
+else
+  gen
+fi