Add product marketing context (week 1 enabler)

Hypothesis: every later copy decision (title/meta rewrites, hosting hub,
CTA blocks) will be written against a single grounded source of truth —
real ICP from GSC query data, verified host prices, and an explicit
never-use list for the site's fabricated proof — instead of being
improvised per page. Metric: none (enabler); success is that week 2's
proof-removal and week 3's CTR rewrites stop inventing claims.

Also stop serving internal strategy publicly: .agents/ and growth/ are
added to .vercelignore (.md was listed but growth/PLAN.md still returns
200 live).

growth/metrics.jsonl

@@ -1 +1,2 @@
 {"ts": "2026-10-24T19:00:18+00:00", "clicks": 9, "impressions": 4745, "ctr": 0.18967334035827188, "position": 24.75, "queries": 447, "page1_zero_queries": 17, "page1_zero_impressions": 1090, "money_impressions": 538, "money_position": 27.5, "visitors": 2, "pageviews": 3, "goals": {"Visit /": 1}}
+{"ts": "2026-10-24T19:00:56+00:00", "clicks": 9, "impressions": 4745, "ctr": 0.18967334035827188, "position": 24.75, "queries": 447, "page1_zero_queries": 17, "page1_zero_impressions": 1090, "money_impressions": 538, "money_position": 27.5, "visitors": 2, "pageviews": 3, "goals": {"Visit /": 1}}