feat(analytics): real Meta + TikTok + YouTube fetchers

[wesleysimplicio]

Context

lib/analytics/{meta,tiktok,youtube}.ts all return seeded deterministic mock numbers from piece_id. Real analytics fetching does not exist.

Goal

Real adapters that pull insights from each platform's API and write to data/analytics.jsonl in the schema documented in DESIGN.md § Data Flow.

Acceptance criteria

• Meta (lib/analytics/meta.ts:25-38): uses Graph API; reads META_ACCESS_TOKEN, META_PAGE_ID; fetches reach, impressions, saves, shares, comments, profile_visits for IG + FB
• TikTok (lib/analytics/tiktok.ts:25-38): uses TikTok Business API; reads TIKTOK_ACCESS_TOKEN; same metrics shape
• YouTube (lib/analytics/youtube.ts:25-38): uses YouTube Data + Analytics APIs; reads YOUTUBE_API_KEY, YOUTUBE_CHANNEL_ID; metric shape + watch_time_s
• All three return { piece_id, platform, reach, impressions, saves, shares, comments, profile_visits, ctr, watch_time_s?, captured_at } matching DESIGN.md
• Each writes one line per fetch to data/analytics.jsonl
• .ralph/analytics-pull.sh calls the real fetchers when DRY_RUN=false, keeps synthetic mode when true
• .env.example adds the new keys with comments on how to obtain them
• E2E specs with mocked HTTP for each adapter

Files

• lib/analytics/{meta,tiktok,youtube}.ts
• .ralph/analytics-pull.sh
• .env.example

[wesleysimplicio]

Closed after PR #40 follow-up stabilization in commit f40b58d. Current main passes npm run typecheck and npm run test:e2e (119 Playwright specs green), and this tracker item is being retired per repository cleanup.