Use schema decoding for Effect parsing paths

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What Changed

• Decode .t3code/vcs.json with Schema.fromJsonString and return Option for missing/invalid config paths instead of JSON.parse/null.
• Decode Windows process diagnostics JSON through Effect Schema and normalize rows with Option.
• Added focused coverage for invalid VCS config JSON and Windows process JSON parsing.

Why

These are small Effect idiom cleanups that make parsing paths more schema-driven, reduce nullable control flow, and keep timeout policy expressed as an effect/Duration.

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

Use schema-based decoding for Windows process JSON and VCS project config parsing

• Replaces loose type-checking in parseWindowsProcessRows with Schema-based decoding; records that fail validation are discarded rather than passed through
• normalizeWindowsProcessRow now strictly requires valid pid, ppid, and a non-empty command, returning Option.none for invalid rows
• parseWindowsProcessRows is now exported and handles both array and single-object JSON responses
• VcsProjectConfig parsing switches to schema-based decoding so invalid or malformed JSON deterministically returns 'auto' instead of throwing
• Behavioral Change: previously accepted Windows process records with missing/invalid fields may now be silently dropped

^{Macroscope summarized cb6fa9c.}