fix: correct \ URL to mimo.xiaomi.com in config

[Ivaloz]

Summary

The \\ field in generated config files was pointing to \https://opencode.ai/config.json\ which is incorrect for MiMo Code. This caused custom provider configurations created via /connect\ to not work properly.

Update all occurrences to use the correct URL: \https://mimo.xiaomi.com/mimocode/config.json\

Changes

• \packages/opencode/src/config/config.ts: Fixed 4 instances of incorrect schema URL

Test Plan

1. Run /connect\ command and create a custom provider
2. Check generated \mimocode.jsonc\ file
3. Verify \\ points to \https://mimo.xiaomi.com/mimocode/config.json\
4. Verify custom provider configuration works correctly

Fixes #1369

[Ivaloz]

简短说明

将配置中默认的 $schema URL 从 https://opencode.ai/config.json 修正为 https://mimo.xiaomi.com/mimocode/config.json，以适配 MiMo Code 场景，修复通过 /connect 生成的自定义 provider 配置无法生效的问题。

为何修改

生成的配置文件里 $schema 指向错误的域名，导致某些配置被误导或无法按 MiMo 的约定解析。本 PR 将所有相关硬编码替换为 MiMo 官方 schema 地址。

如何验证
检出本 PR 分支： gh pr checkout 1505 --repo XiaomiMiMo/MiMo-Code
安装与构建（若仓库使用 pnpm）： pnpm install pnpm -w build
运行 connect 流程并创建 custom provider（按交互完成）： pnpm --filter packages/opencode run connect
定位并检查生成的配置文件（mimocode.jsonc / config.json）： jq -r '."$schema" // "no $schema"' path/to/mimocode.jsonc 期望值： https://mimo.xiaomi.com/mimocode/config.json
在仓库中确认无残留旧 URL： rg "opencode.ai/config.json" || grep -R --line-number "opencode.ai/config.json" .

影响与风险

影响面：配置生成/解析流程。
风险：低（仅替换硬编码常量）。建议合并前做上面验证并搜索残留引用。

回滚/后续

若需回退：回退该提交即可恢复旧行为。
可选后续：若发现仓库其他位置仍用旧 URL，建议一并更新 docs/examples 并在代码旁加一条注释说明该 URL 的用途。

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Short summary

Update the default $schema URL from https://opencode.ai/config.json 到 https://mimo.xiaomi.com/mimocode/config.json so generated configs in MiMo Code workflows point to the correct schema; this fixes custom provider configs created via the /connect flow.

Why

The generated config file previously referenced the wrong domain, which could cause configs to be interpreted incorrectly for MiMo. This PR replaces the hard-coded schema URL with the correct MiMo schema endpoint.

How to verify locally

Check out this PR branch: gh pr checkout 1505 --repo XiaomiMiMo/MiMo-Code
Install & build (example with pnpm): pnpm install pnpm -w build
Run the connect flow and create a custom provider (follow the interactive prompts): pnpm --filter packages/opencode run connect
Locate and inspect the generated config (mimocode.jsonc / config.json): jq -r '."$schema" // "no $schema"' path/to/mimocode.jsonc Expected: https://mimo.xiaomi.com/mimocode/config.json
Confirm no leftover references to the old URL: rg "opencode.ai/config.json" || grep -R --line-number "opencode.ai/config.json" .

Impact & risk

Impact: config generation / parsing flows.
Risk: Low (simple string substitution). Recommend running the above verification and searching the repo for remaining occurrences before merging.

Rollback / follow-up

Rollback: revert this commit to restore previous value.
Follow-up: if other files/docs still refer to the old URL, consider updating them in the same or a follow-up PR and add a short code comment explaining the schema URL purpose.