fix(telnyx): guard voice timeout env values

[aiirvizionz]

Summary

• Guard Telnyx voice gather timeout env parsing against malformed, infinite, zero, and negative values
• Fall back to known-good timeout defaults instead of sending NaN/invalid values to Telnyx
• Include sh1pt site lib tests in Vitest so this regression runs in CI

Why

The Telnyx voice gather payloads used Number(process.env...) directly. If an env value is mistyped, JavaScript can produce NaN, Infinity, or non-positive timeout values that get serialized into the Telnyx request payload instead of falling back to safe defaults.

Tests

• node .\\node_modules\\.pnpm\\vitest@2.1.9_@types+node@22.19.17\\node_modules\\vitest\\vitest.mjs run sites/sh1pt.com/lib/telnyx-voice.test.ts (2 tests passed)
• git diff --check

Note: pnpm exec vitest ... attempted a dependency install first and was blocked by the repo lockfile policy because @profullstack/autoblog@0.4.0 has no tarball integrity field. The direct local Vitest invocation above ran the regression without changing versioned files.

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