feat: support shared local MCP configuration

[MattPua]

Problem

There is no visible way in the Posthog Desktop UI to configure local MCP servers. It just reads from a local ./claude but no way to see what is configured

Changes

Only affects local runs

• add ~/.posthog-code/mcp.json for shared stdio and HTTP MCP servers
• surface and autosave the config from the MCP settings page
• inject supported servers into both local adapters
• validate unsupported entries, secure file writes, and keep cloud import feature-gated

How did you test this?

• 198 focused package tests
• 7 UI tests
• pnpm --filter @posthog/agent build
• affected package and desktop typechecks
• repository commit hook full typecheck
• live Electron MCP settings flow over CDP

Automatic notifications

• Publish to changelog?
• Alert Sales and Marketing teams?

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Created with PostHog Code

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[github-actions]

React Doctor found 1 issue in 1 file · 1 warning.

1 warning

src/features/skills/SkillCodeEditor.tsx

• ⚠️ src/features/skills/SkillCodeEditor.tsx:7 Heavy library loaded eagerly prefer-dynamic-import

_{Reviewed by React Doctor for commit 94fcfdf.}