docs: add first-campaign sections to Google and Meta ad network pages

[samiksha-shreya]

Summary

The Google Ads and Meta Ads pages covered account setup (integration, link IDs, CAPI, event mapping) but never showed how to actually launch a campaign. This adds a numbered "Create Your First Campaign" section to each page, covering app campaigns only (App promotion objective on both platforms, confirmed with the team). Web-driven campaigns stay in the separate Web to App guides. Each section covers prerequisites, the exact campaign-creation flow in the ad platform, and how to verify the campaign appears in Linkrunner. On the Meta page it replaces the old "Campaign Tracking" section, whose content is absorbed into the verification step; existing section anchors keep their numbers. New troubleshooting entries cover campaigns not appearing in Linkrunner.

Screenshots

• Google Ads campaign wizard: 6 annotated retina captures (create button, objective, subtype/app, settings, ad assets, bidding/budget)
• Meta Ads Manager: 4 annotated retina captures (create button, App promotion objective dialog, ad set app store/app name, ad destination with deferred deep link)
• Linkrunner dashboard: Campaigns channel filter with Google and Meta variants

All captures highlight the relevant control in the brand purple with numbered step badges where a shot covers multiple steps, and blur account IDs, campaign names, budgets, app identities, and profile photos. Nothing was published or modified in the ad accounts while capturing.

🤖 Generated with Claude Code