Fix: forward env field from execute to gitCommand in GitVcsDriver

The execute method in GitVcsDriver was silently dropping the env field
from its input when calling gitCommand, and gitCommand's options type
didn't include env at all. This broke CheckpointStore.captureCheckpoint
which passes GIT_INDEX_FILE and author/committer overrides via env,
causing checkpoint git operations to use the user's real index instead
of the temporary one.

Author: cursoragent

apps/server/src/vcs/Layers/GitVcsDriver.ts

@@ -69,6 +69,7 @@ const gitCommand = (
   args: ReadonlyArray<string>,
   options?: {
     readonly stdin?: string;
+    readonly env?: NodeJS.ProcessEnv;
     readonly allowNonZeroExit?: boolean;
     readonly timeoutMs?: number;
     readonly maxOutputBytes?: number;
@@ -81,6 +82,7 @@ const gitCommand = (
     args,
     cwd,
     ...(options?.stdin !== undefined ? { stdin: options.stdin } : {}),
+    ...(options?.env !== undefined ? { env: options.env } : {}),
     ...(options?.allowNonZeroExit !== undefined
       ? { allowNonZeroExit: options.allowNonZeroExit }
       : {}),
@@ -118,6 +120,7 @@ export const makeGitVcsDriver = Effect.fn("makeGitVcsDriver")(function* () {
   const execute: VcsDriverShape["execute"] = (input) =>
     gitCommand(process, input.operation, input.cwd, input.args, {
       ...(input.stdin !== undefined ? { stdin: input.stdin } : {}),
+      ...(input.env !== undefined ? { env: input.env } : {}),
       ...(input.allowNonZeroExit !== undefined ? { allowNonZeroExit: input.allowNonZeroExit } : {}),
       ...(input.timeoutMs !== undefined ? { timeoutMs: input.timeoutMs } : {}),
       ...(input.maxOutputBytes !== undefined ? { maxOutputBytes: input.maxOutputBytes } : {}),