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]>

internal/bot/bot.go

@@ -3,11 +3,13 @@ package bot
 import (
 	"context"
 	"log"
+	"time"
 	"velox-bot/internal/commands"
 	"velox-bot/internal/db/repos/musicrepo"
 	"velox-bot/internal/db/services"
 	"velox-bot/internal/events"
 	"velox-bot/internal/music"
+	"velox-bot/internal/tickets"
 
 	"github.com/bwmarrin/discordgo"
 )
@@ -70,6 +72,18 @@ func (b *Bot) Start() error {
 		}
 	}()
 
+	if st := tickets.Default(); st != nil {
+		go func() {
+			// The connection can drop (database restart, network blip):
+			// reconnect instead of silently ignoring the dashboard from then on.
+			for {
+				err := tickets.StartCommandListener(context.Background(), b.DBHost, b.Session, st)
+				log.Printf("tickets: command listener stopped: %v (retrying in 10s)", err)
+				time.Sleep(10 * time.Second)
+			}
+		}()
+	}
+
 	b.registeredCommands = make([]*discordgo.ApplicationCommand, len(b.Commands))
 	for _, cmd := range b.Commands {
 		created, err := b.Session.ApplicationCommandCreate(b.AppID, b.GuildID, cmd)
@@ -122,6 +136,12 @@ func (b *Bot) Start() error {
 		events.HandleGuildBanRemoveLog(s, m, b.Services)
 	})
 
+	b.Session.AddHandler(func(s *discordgo.Session, t *discordgo.ThreadDelete) {
+		if st := tickets.Default(); st != nil && t.Channel != nil {
+			tickets.ThreadDeleted(context.Background(), st, t.ID)
+		}
+	})
+
 	b.Session.AddHandler(func(s *discordgo.Session, vs *discordgo.VoiceStateUpdate) {
 		events.HandleVoiceStateUpdate(s, vs, b.Services)
 		music.OnVoiceStateUpdate(vs)