fix: prevent context canceled errors in web dashboard

Detach DB queries from HTTP request context so HTMX polling doesn't
cancel in-flight queries when the browser aborts previous XHRs. Add
indexes on login_attempts and sessions to speed up frequent dashboard
queries. Bump version to 0.17.1.

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

cmd/oubliette/main.go

@@ -20,7 +20,7 @@ import (
 	"git.t-juice.club/torjus/oubliette/internal/web"
 )
 
-const Version = "0.17.0"
+const Version = "0.17.1"
 
 func main() {
 	if err := run(); err != nil {