Fix ansible-lint violations: FQCN, formatting, bugs, role renames

- Auto-fix FQCN, YAML formatting, jinja spacing, and free-form module
  syntax via ansible-lint --fix
- Fix comments misplaced inside module args by the auto-fixer
  (bluetooth-monitor, pi_standard_setup, pi_musicmouse)
- Fix notify: references left stale (lowercase) after handler names
  were re-cased, which would have silently broken reboot/restart
  handlers (pi_disable_onboard_bluetooth, pi_hifiberry_amp,
  pi_squeezelite, pi_standard_setup)
- Fix a task in pis/debmatic-install.yml missing its module name
  (apt_repository), which caused a real syntax-check failure
- Add missing play names, fix comment spacing, literal-compare idiom,
  and no-changed-when annotations
- Delete unused/broken roles/better-shell-env (unreferenced, invalid YAML)
- Rename all hyphenated role directories to underscore form to satisfy
  ansible-lint's role-name rule, updating every playbook/meta reference

Remaining lint findings (var-naming, package-latest, risky-file-permissions,
no-handler) intentionally left for follow-up per user decision.

roles/pi_alsasetup/README.md

@@ -0,0 +1,3 @@
+# pi_alsasetup
+
+Syncs the ALSA configuration file to the host.

roles/pi_alsasetup/tasks/main.yml

@@ -0,0 +1,5 @@
+---
+- name: Sync alsa config
+  ansible.builtin.template:
+    src: asound.conf
+    dest: /etc/asound.conf

roles/pi_alsasetup/templates/asound.conf

@@ -0,0 +1,58 @@
+pcm.soundcard {
+   type hw
+   card {{alsa_card_name}}
+}
+
+ctl.dmixer {
+   type hw
+   card {{alsa_card_name}}
+}
+
+pcm.dmixer {
+   type dmix
+   ipc_key 1024
+   slave {
+      pcm "soundcard"
+      channels 2
+   }
+}
+
+pcm.dmixer_plug {
+    type plug
+    slave {
+       pcm "dmixer"
+    }
+}
+
+pcm.softvol_shairport {
+    type softvol
+    slave {
+       pcm   "dmixer_plug"
+    }
+    control {
+       name "ShairPort-Sync Volume"
+       card 0
+    }
+}
+
+pcm.softvol_squeezelite {
+     type softvol
+     slave {
+        pcm "dmixer_plug"
+     }
+     control {
+        name "SqueezeLite Volume"
+        card 0
+     }
+}
+
+pcm.softvol_effects {
+     type softvol
+     slave {
+        pcm "dmixer_plug"
+     }
+     control {
+        name "Effect Volume"
+        card 0
+     }
+}