AMS credentials: update init --interactive to recommend the right credential path per deployment context

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Part of #6844. Depends on #6845 (the credential-recommendation decision this wizard change implements).

Context

init --interactive currently only offers device-flow OAuth as its first claude-cli credential option. Per #6845's recommendation, unattended/fleet-mode deployments should be steered toward ANTHROPIC_API_KEY (or the equivalent for codex-cli) instead of an interactive browser dance that doesn't fit a headless server.

Requirements

• Update init --interactive's wizard flow to offer the credential path AMS credentials: decide the recommended default (subscription OAuth vs API key) for claude-cli and codex-cli #6845 recommends for the operator's actual context, per that issue's decision -- e.g. detecting a non-interactive/no-TTY context and defaulting to prompting for an API key instead of starting a device-flow that requires a browser, or simply presenting API key as an equally-first-class option rather than a fallback.
• Update packages/loopover-miner/DEPLOYMENT.md (and its mirrored apps/loopover-ui/content/docs/ams-deployment.mdx) to document the new recommended path for fleet/server deployments explicitly.

Test Coverage Requirements

Regression tests covering the wizard's new option-selection behavior for both credential paths, plus the existing device-flow-failure-falls-back-to-PAT behavior (unchanged, but must not regress).

Deliverables

• The wizard behavior change and its test coverage.
• The doc updates.

Expected Outcome

A fleet/server operator setting up AMS unattended is guided to the credential path that actually fits their deployment, without needing to already know about ANTHROPIC_API_KEY as an undocumented alternative.

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JSO-4726