feat: support auth-aware generation previews

[mikeylong]

Summary

• add support to
• allow authenticated preview capture to reuse saved Playwright browser state
• keep generation preview capture CLI-only and aligned with session/benchmark flows

Verification

• pnpm --filter @surfaces/interfacectl-cli run build
• pnpm --filter @surfaces/interfacectl-cli exec node --test test/generation-session.test.mjs test/generation-benchmark.test.mjs

[chatgpt-codex-connector]

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[chatgpt-codex-connector]

Treat invalid storage-state files as input errors

If --storage-state points to a file that exists but contains malformed or incompatible Playwright state, browser.newContext throws at this call site before execution reaches the inner try/catch that converts failures into SessionInputError. The outer handler then reports generation-session.internal and returns exit code 1, which misclassifies a user-fixable argument problem and breaks callers that rely on exit code 10 for invalid inputs.

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