Apply idiomatic Effect patterns to SSH diagnostics

[cursor]

What Changed

• Converted @t3tools/ssh error classes from Data.TaggedError to Schema.TaggedErrorClass so they are schema-backed and serializable.
• Replaced Windows process diagnostics JSON.parse with a hoisted Schema.fromJsonString(Schema.Unknown) decoder.
• Updated SSH readiness/desktop SSH consumers to use hoisted Schema.is(...) guards instead of instanceof for schema errors.
• Added targeted coverage for Windows process row decoding through the Effect child process layer.

Why

These are small, focused idiomatic Effect improvements: schema-backed tagged errors support structured runtime checks/serialization, and Schema JSON decoding avoids ad-hoc parsing while preserving existing malformed-row filtering behavior.

UI Changes

Not applicable; 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 (not applicable)
• I included a video for animation/interaction changes (not applicable)

Validation:

• pnpm exec vp test run src/diagnostics/ProcessDiagnostics.test.ts from apps/server passed (7 tests).
• pnpm exec vp test run src/tunnel.test.ts from packages/ssh passed (12 tests).
• pnpm exec vp test run src/ipc/methods/sshEnvironment.test.ts from apps/desktop passed (3 tests).
• pnpm exec vp check passed.
• pnpm exec vp run typecheck passed.

  

Note

Replace instanceof checks with Schema.is guards across SSH error classes

• Reimplements all SSH error classes in packages/ssh/src/errors.ts using Schema.TaggedErrorClass with explicit field schemas, enabling schema-based type guards via Schema.is.
• Replaces instanceof checks with Schema.is-based guards in SSH diagnostics (sshEnvironment.ts, DesktopSshEnvironment.ts, tunnel.ts) so schema-tagged error values are recognized correctly.
• Refactors parseWindowsProcessRows in ProcessDiagnostics.ts to use Schema.decodeUnknownOption instead of a try/catch around JSON.parse.
• Behavioral Change: error detection now matches any schema-conforming value, not just class instances, which matters when errors cross serialization boundaries.

^{Macroscope summarized 7ce32a8.}