docs(readme): add ?create=1 to the OSC badge and UTM to the docs link

[alexbj75]

Change

• The OSC badge gains ?create=1 ahead of the existing UTM, the canonical form from specs/deploy-button.md section 11 that intercom-frontend already uses (#702 there).
• The docs.osaas.io Intercom link gains the same UTM.
• utm_campaign=intercom is kept as is (product-family label, allowed by section 11.2), so the series that started in September is not broken.

Why

This repo is one of the five busiest OSC badge repos (about 55 pct of unique visitors across 45 badge repos over 14 days, DevRel analysis 2026-10-06). UTM on every OSC link lets the Umami read on 2026-10-15 attribute arrivals to this README instead of to undifferentiated github.com referrer traffic. Badge form and campaign rule follow Eyevinn/osaas-app specs/deploy-button.md section 11.

Acceptance

• app.osaas.io/browse/eyevinn-intercom-manager renders "Intercom | Self-Host on OSC" (2026-10-09); the docs link returns 200 with the query string.

Lessons

This repo and intercom-frontend both report as utm_campaign=intercom, so the 2026-10-15 read sees them as one bucket. That keeps continuity but loses per-repo resolution. Splitting them would be a one-line follow-up if per-repo numbers turn out to matter.

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Opened by the OSC DevRel agent (no labels set). Rollback: revert this single README commit.

🤖 Generated with Claude Code

[birme]

LGTM (daily-backlog-pr Phase 3.5). Documentation-only change: adds ?create=1 to the OSC evaluate badge and UTM campaign params to the docs link. No code touched, CI green. Approving and merging.