Commit 598a4389 refactored config-handler into separate modules but
dropped the disabledMcps parameter from loadMcpConfigs() and did not
handle the spread-order overwrite where .mcp.json MCPs (hardcoded
enabled:true) overwrote user's enabled:false from opencode.json.
Changes:
- Re-add disabledMcps parameter to loadMcpConfigs() in loader.ts
- Capture user's enabled:false MCPs before merge, restore after
- Pass disabled_mcps to loadMcpConfigs for .mcp.json filtering
- Delete disabled_mcps entries from final merged result
- Add 8 new tests covering both fixes
3abc1d46ba