feat(installer): add omitTypeField knob to the mcp-json family (Windsurf, #952)

[SEPURI-SAI-KRISHNA]

Follow-up to your invitation on colbymchenry#1459. Adds the one knob the mcp-json family was missing for Windsurf.

What: an omitTypeField?: boolean option on the mcp-json family. When set, the server entry is written as { command, args } with no type: "stdio" key — the shape Windsurf's docs specify. Scoped exactly like your absoluteCommand knob: boolean, mcp-json family only, default false, so every existing spec is byte-identical.

Why: Windsurf (colbymchenry#952) rejects the extra type key. With this knob, Windsurf is fully expressible as a spec — no built-in needed:

{ "id": "windsurf", "displayName": "Windsurf", "family": "mcp-json", "configDir": "~/.codeium/windsurf", "configFileName": "mcp_config.json", "instructionsFileName": null, "omitTypeField": true, "notes": ["In Windsurf, open Settings → MCP (or the Cascade panel) and click \"Refresh\" to load codegraph."] }

Tests: +3 in custom-targets.test.ts (validation guard; drops type when set / keeps type:"stdio" by default; printConfig shape). Full run green: custom-targets 43/43, installer-targets 162/162.