* fix: filter empty messages from polling queries
WhatsApp history sync writes empty protocol artifacts (delivery receipts,
status updates) to the database. On fresh installs, the main channel
(no trigger required) picks these up and spawns a container agent
unnecessarily, causing a message loop on first startup.
Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>
* fix: update test to match empty-content filtering in queries
The getMessagesSince query now filters out empty messages, so the test
should expect 0 results instead of 1.
Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>
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Co-authored-by: Claude Opus 4.6 <noreply@anthropic.com>