Stop the slow test packages waiting (closes #263)

- Tests hash passwords at bcrypt.MinCost, set through the
  PasswordCost field of db.Params. TestPasswordCost checks the
  cost with and without it.
- Test IRC servers check the queue only on broker notification;
  one test keeps the 100 ms fallback poll.
- The stop-timeout test shortens the timeout through a test-only
  setter.
- service and handlers tests build config.Config directly instead
  of through config.New, so they run in parallel. config exports
  DefaultTrustedProxies and ParseTrustedProxies for the handlers
  test config.
- Repeated race trials run as parallel subtests.
- Fixed sleeps become waits on the broker.
- A new test covers the relay's failed queue read, which only the
  100 ms poll had reached.

Model: opus-5-5

internal/handlers/export_test.go

@@ -6,6 +6,10 @@ import (
 	"sneak.berlin/go/neoirc/internal/db"
 )
 
+// MaxLongPollTimeout is the longest HandleGetMessages waits, in
+// seconds.
+const MaxLongPollTimeout = maxLongPollTimeout
+
 // SetPollMessages makes HandleGetMessages read the client
 // output queue with poll in place of Database.PollMessages.
 func (hdlr *Handlers) SetPollMessages(