Fix deployment issues and add threads, numbered watchlist, search URL encoding

- Fix SQLite connection string (drop query param, use explicit PRAGMA)
- Register sqlite3-fk-wal driver for mautrix cryptohelper (pure Go, no CGO)
- Fetch DeviceID via /whoami when using bare access token
- Log cross-signing results at Warn/Info instead of Debug
- Post deals into Matrix threads: Game Deals, DLC Deals, Epic Free Games
- Add numbered watchlist; !extend and !unwatch accept list numbers
- URL-encode search queries for multi-word !search commands
- Add GetConfig/SetConfig helpers for persistent thread event IDs

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

internal/matrix/sqlitedriver.go

@@ -0,0 +1,36 @@
+package matrix
+
+import (
+	"database/sql"
+	"database/sql/driver"
+
+	sqlite "modernc.org/sqlite"
+)
+
+type fkWALDriver struct {
+	inner *sqlite.Driver
+}
+
+func (d *fkWALDriver) Open(name string) (driver.Conn, error) {
+	conn, err := d.inner.Open(name)
+	if err != nil {
+		return nil, err
+	}
+	execer := conn.(driver.Execer)
+	for _, pragma := range []string{
+		"PRAGMA foreign_keys = ON",
+		"PRAGMA journal_mode = WAL",
+		"PRAGMA synchronous = NORMAL",
+		"PRAGMA busy_timeout = 5000",
+	} {
+		if _, err := execer.Exec(pragma, nil); err != nil {
+			conn.Close()
+			return nil, err
+		}
+	}
+	return conn, nil
+}
+
+func init() {
+	sql.Register("sqlite3-fk-wal", &fkWALDriver{inner: &sqlite.Driver{}})
+}