Add support tickets that work with private threads

Members open a ticket from a panel in the ticket channel: one button per
category (a dropdown past five), then a short form. Each ticket is a private
thread named after the category, number and opener, with a first message
that mentions the category's staff role so its members join, and Claim and
Close buttons.

- Claim: staff (the category's role, or Manage Threads / Manage Server)
  take a ticket; the first message shows who has it.
- Close: the opener or staff close it, with an optional reason. The thread
  is locked and archived, and the log channel gets a summary and a .txt
  transcript of the whole thread.
- /ticket add|remove|claim|close inside a ticket; /tickets setup,
  /tickets category add|remove|list and /tickets panel for admins.
- Per-member limit on open tickets (default 1), per-server ticket numbers
  handed out atomically, a deleted thread closes its ticket.
- The dashboard asks the bot to post or refresh the panel through
  ticket_commands (LISTEN/NOTIFY, like music); the listener reconnects if
  the database connection drops.
- Setup warns about missing bot permissions in the ticket and log channels.

The flows live in internal/tickets behind small Discord and store
interfaces, with unit tests on fakes; the repo and the listener have
integration tests (-tags integration, TICKETS_TEST_DB).

Needs the ticket tables (velox-dashboard-api migration 000016_tickets).
.gitignore gains the /tldr benchmark rules so private chat exports and
benchmark results on disk can't be committed from this branch.

Co-Authored-By: Claude Opus 5.5 <[email protected]>

main.go

@@ -8,6 +8,7 @@ import (
 	"syscall"
 	"velox-bot/internal/bot"
 	"velox-bot/internal/commands"
+	cmdtickets "velox-bot/internal/commands/tickets"
 	"velox-bot/internal/config"
 	"velox-bot/internal/db"
 	"velox-bot/internal/db/repos/defaultrolerepo"
@@ -17,6 +18,7 @@ import (
 	"velox-bot/internal/db/repos/rpsrepo"
 	"velox-bot/internal/db/repos/schedulerepo"
 	"velox-bot/internal/db/repos/settingsrepo"
+	"velox-bot/internal/db/repos/ticketrepo"
 	"velox-bot/internal/db/repos/twitchrepo"
 	"velox-bot/internal/db/repos/usersettingsrepo"
 	"velox-bot/internal/db/repos/welcomerepo"
@@ -59,6 +61,7 @@ func main() {
 	welcomeRepo := welcomerepo.NewRepo(db)
 	twitchRepo := twitchrepo.NewRepo(db)
 	defaultRoleRepo := defaultrolerepo.NewRepo(db)
+	cmdtickets.Init(ticketrepo.NewRepo(db))
 	levelService := level.New(levelRepo, settingsRepo)
 	levelSettingsService := levelsettings.New(settingsRepo)
 	logSettingsService := logsettings.New(settingsRepo)