Remove dormant VPN tooling from extension source

[StarlightDaemon]

This PR removes dormant VPN runtime and test files from the extension source.

Changes:

• Deleted extension/src/shared/lib/vpn/VPNProviderRanges.ts
• Deleted extension/src/shared/lib/vpn/VPNService.ts
• Deleted extension/src/shared/ui/VPNIndicator.tsx
• Deleted extension/tests/unit/VPNService.test.ts

Validation Status:

• Verified that no active product entrypoints depended on these files.
• Full validation suite (compile, test, build) was confirmed green in prior steps.
• Incidental churn in buildInfo.ts was restored to prevent noise.

Note:

• No archival documentation (e.g., in docs/ or agent-ledger/) was purged in this scope.