fix(components): isolate onboarding tour cloud access [risk:medium]

[Leeeon233]

Risk: 🟡 medium | Confidence: high — isolates the Electron onboarding tour from the outer authenticated cloud adapter; provider wiring and escape paths are covered by regression tests

Summary

• wrap the production-component onboarding tour in an isolated platform and authenticated cloud boundary
• serve tour machine and local-project fixtures locally while rejecting writes and containing unknown reads
• add wiring-level regression coverage so the tour cannot query the real backend again

Verification

• pnpm check:affected
• components typecheck
• onboarding isolation tests: 17 passed
• adversarial client and scope review completed

[github-actions]

@Leeeon233, this pull request changes 467 lines (additions + deletions) without linking a prior Lody issue.

It is marked status:pr-too-large. The PR-body policy gives you seven days from the first invalid-body notice to fix the description. Open an issue, wait for maintainers to explicitly agree on the scope and approach, then add its full URL to ## Related issue. Creating an issue yourself is not approval.

The size warning clears automatically after a valid Issue URL is linked. If the PR body remains invalid for seven days, the shared expiry policy closes the PR and requires a new submission; automation verifies the URL but maintainers decide whether prior agreement is sufficient.

[github-actions]

@Leeeon233, this pull request body does not match Lody's PR template.

This PR is marked status:needs-pr-body. Update the description and satisfy every required section by 2026-09-04 13:40:46 UTC. The label and this comment are removed automatically after the body passes validation.

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Checker findings

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