Cover Name(), String(), Code(), Int(), FromInt() for known and unknown
numerics, plus the deprecated Name() package-level function.
100% statement coverage on pkg/irc.
- Rename MessageType to IRCMessageType (custom int type)
- .Name() returns just the name (e.g. "RPL_LUSEROP")
- .String() returns name + code (e.g. "RPL_LUSEROP <252>")
- .Code() returns zero-padded 3-digit string (e.g. "252")
- .Int() returns the bare int value
- Add FromInt() package-level function with validation
- Update all call sites to use new type and methods
- Create 'type MessageType int' in pkg/irc/numerics.go
- Type all Rpl*/Err* numeric constants as MessageType
- Add Name() method returning the standard IRC name (e.g. RPL_WELCOME)
- Add String() method returning zero-padded numeric (e.g. 001)
- Update enqueueNumeric/respondIRCError to accept MessageType
- Update internal/db to use MessageType conversion for Name() calls
- Change names map key type from int to MessageType
Refs #52
