Use more idiomatic Effect services and durations

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What Changed

• Added an Effect Context.Service for server environment label command execution and updated tests to use Layer.mock plus assert instead of module mocks/expect.
• Added a structured Schema.TaggedErrorClass for label command failures.
• Reworked SSH command/readiness timeout options and constants to use Duration.Input / Duration instead of millisecond-only fields.

Why

This keeps command execution mockable through Effect layers, makes failures typed and structured, and moves timeout policies toward Effect's native duration primitives.

UI Changes

Not applicable.

Checklist

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

  

Note

Replace numeric millisecond timeouts and null returns with Effect Duration and Option types

• Replaces raw millisecond numbers in RunSshCommandOptions and waitForHttpReady with Duration.Input parameters; internal constants in tunnel.ts and command.ts are also converted to Duration values.
• Replaces string | null returns with Option<string> throughout ServerEnvironmentLabel.ts for normalizeLabel, parseMachineInfoValue, readLinuxMachineInfo, and related helpers.
• Extracts command execution in ServerEnvironmentLabel into an injectable ServerEnvironmentLabelCommandRunner service, with a live layer backed by ChildProcessSpawner and a structured ServerEnvironmentLabelCommandError type.
• Behavioral Change: RunSshCommandOptions.timeoutMs is replaced by timeout?: Duration.Input; callers passing a raw number must update to a Duration value.

^{Macroscope summarized 6240442.}