Glama: dovecot sieve cannot write spam-global.svbin (read-only), warning on every delivery

Imported from GitHub issue El-SaMa/oma#142 by @El-SaMa.

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Every local delivery on Glama logs:

lmtp(...): Error: open(/etc/dovecot/spam-global.svbin.glama.lanetti.fi....) failed: Read-only file system
sieve: binary /etc/dovecot/spam-global.svbin: save: failed to create temporary file

Mail is still stored (stored mail into mailbox 'INBOX'), so this is noise plus a recompile of the global spam sieve on every message.

Careful

CLAUDE.md: mail on Glama goes through the Enhance API, and appcd/Enhance-owned files are not hand-edited. Investigate whether Enhance ships a precompiled spam-global.svbin or a writable location. If it needs a config change, get operator approval and prefer the Enhance-supported way.

Done when

The cause is understood and either fixed the supported way or documented as harmless Enhance behaviour.