_tool_remember and on_memory_write were posting memories as session
messages that depend on commit-time VLM extraction to persist. With
extraction_enabled: false (no VLM configured), the extraction pipeline
never processes these messages, causing memories to be silently lost.
Replace both paths with direct POST to /api/v1/content/write?mode=create,
which creates the file, stores the content, and queues vector indexing
in a single API call. Error reporting is immediate — no silent failures.
- Maps viking_remember category to viking:// subdirectory
- Generates UUID-based URIs via uuid4().hex[:12]
- Returns byte count in confirmation message
2d587c5662