Preserve PortScanner probe defects

[juliusmarminge]

Summary

• recover only expected typed ProcessRunner failures from platform port probes
• retain defects and interruption instead of silently falling back
• log the structured process error with probe and host-platform context before fallback

Validation

• vp test apps/server/src/preview/PortScanner.test.ts
• vp check
• vp run typecheck

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Note

Low Risk
Localized preview port-scan error handling with clearer failure semantics; no auth, data, or security surface changes.

Overview
Port discovery no longer treats every process-probe failure the same: lsof / Windows listener probes used a broad catchCause that turned any failure (including defects and cancellation) into a silent fallback to common-port scanning.

They now catchTags only the expected ProcessRunner failures (ProcessSpawnError, stdin/output/read/timeout errors). Those paths log debug context (probe name, platform, error) via recoverProcessProbeFailure and still fall back to common-port probes. Defects and interruptions propagate instead of being swallowed.

Tests add makeProbeFailureLayer and assert scan() fails with dies/interrupts-only causes when the injected probe does.

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Note

Preserve PortScanner probe defects and interruptions instead of swallowing them

• Replaces broad catchCause handlers in PortScanner.ts with targeted catchTags covering only specific process failures (ProcessSpawnError, ProcessStdinError, ProcessOutputLimitError, ProcessReadError, ProcessTimeoutError).
• Defects and interruptions from the Windows powershell and lsof probes now propagate to callers instead of being silently swallowed.
• Adds a recoverProcessProbeFailure helper that logs a debug message (with probe type, platform, and error) before returning null to trigger fallback to common-port probing.
• Adds two new tests in PortScanner.test.ts verifying that defects and interruptions from process probes are preserved in the failure cause.
• Behavioral Change: any code that previously relied on PortDiscovery.scan succeeding despite probe defects or interruptions will now see those failures propagate.

^{Macroscope summarized ac9be89.}

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[macroscopeapp]

Approvability

Verdict: Approved

Straightforward bug fix that replaces overly broad error catching with specific error types, allowing defects and interruptions to properly propagate instead of being silently swallowed. Well-tested and self-contained to PortScanner error handling.

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Dismissing prior approval to re-evaluate ac9be89