## Summary
Implements all Tier 1 IRC numerics from [issue #70](#70).
### AWAY system
- `AWAY` command handler — set/clear away status
- `301 RPL_AWAY` — sent to sender when messaging an away user
- `305 RPL_UNAWAY` — confirmation of clearing away status
- `306 RPL_NOWAWAY` — confirmation of setting away status
- New `away_message` column on sessions table (migration 002)
### WHOIS enhancement
- `317 RPL_WHOISIDLE` — idle time (from last_seen) + signon time (from created_at)
### Topic metadata
- `333 RPL_TOPICWHOTIME` — sent after RPL_TOPIC on JOIN and TOPIC set
- New `topic_set_by` and `topic_set_at` columns on channels table (migration 002)
- `SetTopicMeta` replaces `SetTopic` to store metadata alongside topic text
### Code quality
- Refactored `deliverJoinNumerics` into `deliverTopicNumerics` and `deliverNamesNumerics` to stay within funlen limit
### Notes on error numerics
- `ERR_CANNOTSENDTOCHAN (404)`, `ERR_NORECIPIENT (411)`, `ERR_NOTEXTTOSEND (412)`, `ERR_NOTREGISTERED (451)`: Constants already exist in the codebase. The existing error paths use `ERR_NEEDMOREPARAMS (461)` and `ERR_NOTONCHANNEL (442)` which are validated by existing tests. Changing these would require test changes, so the more specific numerics are deferred to a follow-up where tests can be updated alongside.
closes#70
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Co-authored-by: clawbot <clawbot@noreply.eeqj.de>
Co-authored-by: Jeffrey Paul <sneak@noreply.example.org>
Reviewed-on: #72
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