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/server_link_aggregation/README.md

@@ -0,0 +1,4 @@
+# server_link_aggregation
+
+Configures a network interface file for link aggregation (bonding) on the
+server.

roles/server_link_aggregation/files/interfaces

@@ -0,0 +1,20 @@
+source /etc/network/interfaces.d/*
+
+# The loopback network interface
+auto lo
+iface lo inet loopback
+
+## The primary network interface
+#allow-hotplug enp2s0
+#iface enp2s0 inet dhcp
+## This is an autoconfigured IPv6 interface
+#iface enp2s0 inet6 auto
+
+auto bond0
+
+iface bond0 inet dhcp 
+  bond-slaves enp3s0 enp4s0 enp5s0
+  bond-mode 802.3ad
+  bond-lacp-rate 1
+  bond-miimon 100
+  bond-xmit-hash-policy layer3+4

roles/server_link_aggregation/tasks/main.yml

@@ -0,0 +1,9 @@
+---
+- name: Apt install download & unzip packages
+  ansible.builtin.apt:
+    name:
+      - ifenslave
+- name: Interface file
+  ansible.builtin.copy:
+    src: interfaces
+    dest: /etc/network/interfaces