Fixes #6674

/claim #6674

Summary

• Replace panic on missing dialers in loader with a returned error.
• Update Store.Load, LoadTemplates, and LoadTemplatesWithTags to propagate errors.
• Update callers (runner, sdk, integration paths, automaticscan, lazy auth path) to handle returned errors.
• Replace waitgroup creation panic with wrapped error return.
• Add regression test asserting missing dialers returns a proper error.

Why

Template loading can be called from flows where dialers are not initialized. Panicking crashes the process; returning errors lets callers handle the condition gracefully.

Summary by CodeRabbit

• Bug Fixes
  • Improved template-loading error handling across the app: failures are now detected, surfaced with clearer messages, and cause early termination instead of being ignored. This yields more reliable behavior and easier diagnosis for template issues. Also added checks to report ambiguous/multiple template matches and missing template infrastructure so such problems are flagged to users.