WhatsApp Cloud API template sync currently fails silently — if the Graph
API call errors (expired token, rate limit, permission issue), the
channel simply keeps its stale templates with no trace in the logs. This
adds a warning log when the template fetch fails, so failed syncs are
visible and debuggable.
## What changed
- `Whatsapp::Providers::WhatsappCloudService#fetch_whatsapp_templates`
now logs a warning with the account id, inbox id, HTTP status code, and
Meta's error message when the response is not successful.
- The inbox id uses safe navigation since sync also runs from the
channel's `after_create` callback, before the inbox record exists.
- The request URL is intentionally not logged, as it contains the access
token as a query param.
## How to reproduce
1. Set up a WhatsApp Cloud inbox with an invalid/expired `api_key`.
2. Trigger a template sync (Inbox settings → sync templates, or wait for
the scheduler).
3. Previously nothing was logged; now a `[WHATSAPP] Template sync failed
for account ... inbox ...` warning appears in the Rails logs.
🤖 Generated with [Claude Code](https://claude.com/claude-code)
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Co-authored-by: Muhsin <12408980+muhsin-k@users.noreply.github.com>
