Add space groups, fix HLTB scraper, fix quote wall E2EE, improve tarot prompts

Space groups: automatic room grouping via membership overlap percentage.
Rooms with sufficient shared members are grouped together so leaderboards,
trivia scores, and stats aggregate across the community. Uses strict
clique-based algorithm (every room must meet threshold with every other
room in group). Configurable via SPACE_GROUP_THRESHOLD env var. Persisted
to SQLite, recomputed hourly and on startup.

HLTB scraper: rewrote for new howlongtobeat.com API (two-step token auth
via /api/finder/init + /api/finder endpoint).

Quote wall: fix E2EE decrypt flow for reply-to-save (ParseRaw before
Decrypt, skip ParseRaw after Decrypt returns pre-parsed event). Fix
subcommand matching for delete/search. Remove broken star-reaction handler
and old quote handler from user.go.

Other fixes:
- Strip Matrix reply fallback before command detection (main.go)
- Increase Ollama context window to 8192
- Improve tarot spread prompts (~4x longer, narrative arc)
- Add "cards are props" instruction to tarot LLM prompt
- Fix movies.go CommandDef name mismatch
- Add Community category to !help
- Remove daily horoscope broadcast cron
- Update README with all changes

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

main.go

@@ -147,6 +147,9 @@ func main() {
 		os.Exit(1)
 	}
 
+	// Initialize space groups (room overlap detection for community-wide leaderboards)
+	plugin.InitSpaceGroups(client)
+
 	// ---- Set up event handlers ----
 
 	syncer := client.Syncer.(*mautrix.DefaultSyncer)
@@ -179,6 +182,12 @@ func main() {
 		}
 
 		body := content.Body
+		// Strip Matrix reply fallback: "> <@user:server> ..." lines followed by blank line
+		if strings.HasPrefix(body, "> <@") || strings.HasPrefix(body, "> * <@") {
+			if idx := strings.Index(body, "\n\n"); idx >= 0 {
+				body = strings.TrimSpace(body[idx+2:])
+			}
+		}
 		msgCtx := plugin.MessageContext{
 			RoomID:    evt.RoomID,
 			EventID:   evt.ID,
@@ -216,7 +225,7 @@ func main() {
 
 	// ---- Set up cron scheduler ----
 	scheduler := cron.New()
-	setupScheduledJobs(scheduler, client, wotdPlugin, holidaysPlugin, gamingPlugin, birthdayPlugin, animePlugin, moviesPlugin, concertsPlugin, esteemedPlugin, horoscopePlugin)
+	setupScheduledJobs(scheduler, client, wotdPlugin, holidaysPlugin, gamingPlugin, birthdayPlugin, animePlugin, moviesPlugin, concertsPlugin, esteemedPlugin)
 	scheduler.Start()
 
 	// ---- Start syncing ----
@@ -252,7 +261,6 @@ func setupScheduledJobs(
 	movies *plugin.MoviesPlugin,
 	concerts *plugin.ConcertsPlugin,
 	esteemed *plugin.EsteemPlugin,
-	horoscope *plugin.HoroscopePlugin,
 ) {
 	rooms := getRooms()
 
@@ -271,14 +279,6 @@ func setupScheduledJobs(
 		}
 	})
 
-	// Daily horoscopes at 06:30
-	c.AddFunc("30 6 * * *", func() {
-		slog.Info("scheduler: posting daily horoscopes")
-		for _, r := range rooms {
-			horoscope.PostDailyHoroscopes(r)
-		}
-	})
-
 	// Holidays at 07:00
 	c.AddFunc("0 7 * * *", func() {
 		slog.Info("scheduler: posting holidays")
@@ -338,6 +338,12 @@ func setupScheduledJobs(
 		esteemed.PostWeekly()
 	})
 
+	// Space groups refresh every hour
+	c.AddFunc("0 * * * *", func() {
+		slog.Info("scheduler: refreshing space groups")
+		plugin.RefreshSpaceGroups()
+	})
+
 	// Database maintenance at 03:00 daily
 	c.AddFunc("0 3 * * *", func() {
 		slog.Info("scheduler: running database maintenance")