docs(box): add git config params and endpoint docs

box/overall/git.mdx

@@ -8,7 +8,11 @@ Clone a repository, inspect changes, commit work, push a branch, or open a pull
 
 ## Configure Git Access
 
-If you want to work with private repositories, push changes, or create pull requests, create the box with a GitHub token.
+Pass a `git` config to `Box.create` to configure Git access. All fields are optional.
+
+- **`token`** — GitHub token. Required for private repositories, pushing, and creating pull requests.
+- **`userName`** — Git user name written to the container's global git config on creation. Defaults to `"Upstash Box"`.
+- **`userEmail`** — Git user email written to the container's global git config on creation. Defaults to `"box@upstash.com"`.
 
 <Note>
   For a fine-grained token, the following permissions are sufficient for basic usage:
@@ -21,13 +25,15 @@ UPSTASH_BOX_API_KEY=abx_xxxxxxxxxxxxxxxxxxxxxxxx
 GITHUB_TOKEN=ghp_xxxxxxxxxxxxxxxxxxxxxxxx
 ```
 
-```tsx {5-7}
+```tsx {5-10}
 import { Box } from "@upstash/box"
 
 const box = await Box.create({
   runtime: "node",
   git: {
-    token: process.env.GITHUB_TOKEN,
+    token: process.env.GITHUB_TOKEN,  // optional — required for private repos / push / PRs
+    userName: "release-bot",          // optional — defaults to "Upstash Box"
+    userEmail: "bot@acme.com",        // optional — defaults to "box@upstash.com"
   },
 })
 ```
@@ -144,6 +150,39 @@ const commit = await box.git.commit({
 })
 ```
 
+Use `authorName` and `authorEmail` to override the git identity for this commit only. If omitted, the identity configured on the box (via `Box.create` or `updateConfig`) is used.
+
+```tsx
+const commit = await box.git.commit({
+  message: "feat: add onboarding checklist",
+  authorName: "Alice",           // optional — overrides git identity for this commit only
+  authorEmail: "alice@acme.com", // optional — overrides git identity for this commit only
+})
+```
+
+### Update Git Config
+
+Updates the git identity (`userName` and/or `userEmail`) applied to the container. Partial updates are supported — you can update either field independently. At least one field is required.
+
+Returns the effective identity values after the update. If the box is running or idle, the new config is applied immediately inside the container.
+
+```tsx
+const config = await box.git.updateConfig({
+  userName: "release-bot",
+  userEmail: "release@acme.com",
+})
+
+console.log(config.git_user_name)  // "release-bot"
+console.log(config.git_user_email) // "release@acme.com"
+```
+
+```tsx
+// 👇 partial update — change only one field
+const config = await box.git.updateConfig({
+  userEmail: "ci@acme.com",
+})
+```
+
 ### Push
 
 Pushes the current branch. You can also provide a branch name explicitly.