feat: account enrichment using context.dev [UPM-27] (#13978)

## Account branding enrichment during signup

This PR does the following

### Replace Firecrawl with Context.dev

Switches the enterprise brand lookup from Firecrawl to Context.dev for
better data quality, built-in caching, and automatic filtering of
free/disposable email providers. The service interface changes from URL
to email input to match Context.dev's email endpoint. OSS still falls
back to basic HTML scraping with a normalized output shape across both
paths.

The enterprise path intentionally does not fall back to HTML scraping on
failure — speed matters more than completeness. We want the user on the
editable onboarding form fast, and a slow fallback scrape is worse than
letting them fill it in.

Requires `CONTEXT_DEV_API_KEY` in Super Admin → App Config. Without it,
falls back to OSS HTML scraping.

### Add job to enrich account details

After account creation, `Account::BrandingEnrichmentJob` looks up the
signup email and pre-fills the account name, colors, logos, social
links, and industry into `custom_attributes['brand_info']`.

The job signals completion via a short-lived Redis key (30s TTL) + an
ActionCable broadcast (`account.enrichment_completed`). The Redis key
lets the frontend distinguish "still running" from "finished with no
results."

config/installation_config.yml

@@ -211,6 +211,13 @@
   type: code
 # End of Captain Config
 
+# ------- Context.dev Config ------- #
+- name: CONTEXT_DEV_API_KEY
+  display_title: 'Context.dev API Key'
+  description: 'API key for Context.dev branding service used during account onboarding'
+  type: secret
+# ------- End of Context.dev Config ------- #
+
 # ------- Chatwoot Internal Config for Cloud ----#
 - name: CHATWOOT_INBOX_TOKEN
   value: