feat: unified MCP setup via chezmoidata

[devin-ai-integration]

Summary

MCP server declarations moved to a single .chezmoidata.yaml source of truth, with platform-specific run_onchange_ scripts that execute devin mcp add / claude mcp add CLI commands (remove-then-add pattern for idempotent updates).

# .chezmoidata.yaml
mcp_servers:
  stdio: { context7, heroui-react, heroui-native }
  http:  { deepwiki }

Scripts use command -v / Get-Command to skip missing CLIs, and a # hash: comment triggers re-execution only when declarations change.

Other changes:

• mcpServers removed from config.json (both Linux and Windows paths) — now managed by CLI
• dot_claude/settings.json added ({"theme": "dark"} → ~/.claude/settings.json)

Link to Devin session: https://app.devin.ai/sessions/c5a2e37f435e42c08adf79c46ce59b0e
Requested by: @caipira113

[devin-ai-integration]

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