chore(e2e): tag suite traffic with x-client-type: test

[vreshch]

Why

Estate test-traffic contract: every e2e/synthetic request must carry x-client-type: test. The edge classifier (Traefik -> Vector) and @agentage/observability span stamping key on exactly this header; UA sniffing is only a fallback. This suite signs up throwaway accounts against a live Better Auth AS (auth.<AGENTAGE_SITE_FQDN>), all of it untagged today.

What

• New e2e/client-type.ts - single source for the header (local const; no shared package here).
• playwright.config.ts gains a use.extraHTTPHeaders default (the config had no use block at all).
• e2e/helpers.ts newBrowserContext(): apiRequest.newContext passes its own extraHTTPHeaders (Origin), which REPLACES the config default per key - so it spreads the tag explicitly.
• The daemon MCP RPC helpers in mcp-contract.test.ts / mcp-daemon.test.ts tag their fetch too (loopback today, but keeps the contract uniform).

Known gap

Requests the CLI subprocess makes to the live stack (OAuth, sync over git smart-HTTP) still go out untagged - the test harness cannot inject a header into the built binary. Closing that needs a client-side hook in the CLI itself (e.g. honoring an AGENTAGE_CLIENT_TYPE env var); flagged, not fixed here.

Verified

prettier --check clean; playwright test --list loads the config (44 tests in 11 files). No suite run against a deployed stack.

[github-actions]

🎉 PR Validation ✅ PASSED

Commit: ea43502a1080b06b5e8043825b4c1bcb4e2ed902
Branch: chore/e2e-client-type-header

Checks:

• ✅ Release guard (no version/changelog changes)
• ✅ Dependencies installed
• ✅ Type check passed
• ✅ Linting passed
• ✅ Format check passed
• ✅ Tests + coverage passed
• ✅ Build successful

Ready to merge! ✨

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⏰ Generated at: 2026-08-14T16:54:30.665Z