## Problem
Channel API endpoints scan entire DB — 2.4s for channel list, 30s for
messages.
## Fix
- Added `channel_hash` column to transmissions (populated on ingest,
backfilled on startup)
- `GetChannels()` rewrites to GROUP BY channel_hash (one row per channel
vs scanning every packet)
- `GetChannelMessages()` filters by channel_hash at SQL level with
proper LIMIT/OFFSET
- 60s cache for channel list
- Index: `idx_tx_channel_hash` for fast lookups
Expected: 2.4s → <100ms for list, 30s → <500ms for messages.
Fixes#762
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Co-authored-by: you <you@example.com>
## Problem
Channels page shows 53K 'Unknown' messages — undecryptable GRP_TXT
packets with no content. Pure noise.
## Fix
- Backend: channels API filters out undecrypted messages by default
- `?includeEncrypted=true` param to include them
- Frontend: 'Show encrypted' toggle in channels sidebar
- Unknown channels grayed out with '(no key)' label
- Toggle persists in localStorage
Fixes#727
---------
Co-authored-by: you <you@example.com>
Kpa-clawbot