Improve idiomatic Effect usage in config and Tailscale paths

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What Changed

• Replaced manual VCS project config JSON.parse/null flow with shared Schema lenient JSON decoding and Option handling.
• Added VCS config tests for malformed JSON and schema-invalid VCS kind fallback behavior.
• Replaced Tailscale raw timeout millisecond constants with Duration values and Duration.Input timeout wiring.
• Added a deterministic TestClock timeout test for readTailscaleStatus.

Why

These are small, focused idiomatic Effect improvements that make parsing and timeout behavior easier to test and maintain without escaping to ad-hoc JSON parsing or real-time waits.

UI Changes

N/A - no UI changes.

Checklist

• This PR is small and focused
• I explained what changed and why
• I included before/after screenshots for any UI changes (N/A)
• I included a video for animation/interaction changes (N/A)

  

Note

Refactor VCS config parsing and Tailscale timeouts to use idiomatic Effect patterns

• Replaces manual null checks in VcsProjectConfig with Option-based control flow; malformed or schema-invalid JSON in .t3code/vcs.json now falls back to 'auto' with a warning log instead of propagating errors.
• Converts Tailscale timeout constants from raw millisecond numbers to Duration-typed values (TAILSCALE_STATUS_TIMEOUT, TAILSCALE_SERVE_TIMEOUT, TAILSCALE_PROBE_TIMEOUT) and updates all call sites.
• Adds test coverage for malformed JSON, invalid config kinds, and deterministic timeout behavior via TestClock.
• Behavioral Change: probeTailscaleHttpsEndpoint callers must now pass timeout: Duration.Input instead of timeoutMs: number.

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[github-actions]

🚀 Expo continuous deployment is ready!

• Project → t3-code
• Platforms → android, ios
• Scheme → t3code-preview

	🤖 Android	🍎 iOS
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Build Details	Build Permalink Details Distribution: INTERNAL Build profile: preview:dev Runtime version: ae17d94b35f91f9c608a63dadbc3ddd9f4ba056e App version: 0.1.0 Git commit: afda6b0090c744f0262bdd2eb168f1521603e626	Build Permalink Details Distribution: INTERNAL Build profile: preview:dev Runtime version: 313e506a7f15a9c3f15b01d787d68a12382432bf App version: 0.1.0 Git commit: afda6b0090c744f0262bdd2eb168f1521603e626
Update Details	Update Permalink Details Branch: pr-3073 Runtime version: ae17d94b35f91f9c608a63dadbc3ddd9f4ba056e Git commit: afda6b0090c744f0262bdd2eb168f1521603e626	Update Permalink Details Branch: pr-3073 Runtime version: 313e506a7f15a9c3f15b01d787d68a12382432bf Git commit: afda6b0090c744f0262bdd2eb168f1521603e626
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