Stop the delegated frontend build from sudoing on the control machine

pi_standard_setup's defaults set `ansible_become: true`. Role defaults are
play-wide host variables, and in Ansible's precedence the `ansible_become`
variable outranks the `become` keyword - so the `become: false` on every
pi_musicmouse task delegated to localhost was silently overridden and each one
tried to sudo on the machine running ansible:

    Premature end of stream waiting for become success or become password prompt

Those defaults earn their keep bootstrapping a fresh Pi, where you connect as
`pi` and become root to enable root login, so override the variable on the
delegated tasks rather than removing them.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>

roles/pi_musicmouse/handlers/main.yml

@@ -11,6 +11,8 @@
     chdir: "{{ pi_musicmouse_build_cache }}/{{ musicmouse_version | regex_replace('/', '_') }}/web"
   delegate_to: localhost
   become: false
+  vars:
+    ansible_become: false  # see the first delegated task in tasks/main.yml
   changed_when: true
   notify: Compile frontend
 
@@ -20,6 +22,8 @@
     chdir: "{{ pi_musicmouse_build_cache }}/{{ musicmouse_version | regex_replace('/', '_') }}/web"
   delegate_to: localhost
   become: false
+  vars:
+    ansible_become: false  # see the first delegated task in tasks/main.yml
   changed_when: true
   notify: Sync frontend