feat(dovecot): add support for configuring imap_capability

This introduces the `dovecot_imap_capability` variable to allow customization of advertised IMAP capabilities.

- Add `dovecot_imap_capability` to `defaults/main.yml` (defaulting to empty).
- Update `templates/dovecot.conf.j2` to conditionally include the `protocol imap` block if the capability string is provided.
- This enables operators to add or remove specific IMAP extensions (e.g., disabling `LITERAL+` or `NOTIFY`) for client compatibility.

defaults/main.yml

@@ -45,6 +45,13 @@ dovecot_enabled: true
 # Protocols to enable (imap, pop3, lmtp)
 dovecot_protocols: "imap pop3 lmtp"
 
+# IMAP capability adjustments. Set to modify advertised IMAP capabilities.
+# Use +CAPABILITY to add, -CAPABILITY to remove.
+# Example: "+IMAP4rev1 -LITERAL+ -NOTIFY" removes modern extensions that
+# might suppress standard untagged responses.
+# Leave empty to use Dovecot defaults.
+dovecot_imap_capability: ""
+
 # Mail storage location. Using Maildir in the user's home directory.
 dovecot_mail_location: "maildir:~/Maildir"
 

templates/dovecot.conf.j2

@@ -2,6 +2,12 @@
 # Ansible managed: {{ ansible_managed }}
 
 protocols = {{ dovecot_protocols }}
+{% if dovecot_imap_capability | default('') | length > 0 %}
+
+protocol imap {
+  imap_capability = {{ dovecot_imap_capability }}
+}
+{% endif %}
 
 # Dictionary of configuration files
 !include conf.d/*.conf