fix(workspace): preserve git env for remote clones

[christso]

Summary

• preserve the inherited process environment when allagents shells out to git
• keep non-interactive git safeguards while allowing user git config and credentials to remain available
• apply the same env handling to managed repository clone/pull paths and cover the helper with a unit test

Reproduction

npx allagents@next workspace init ./cargowise-allagents-1 --from https://github.com/WiseTechGlobal/WTG.AI.Prompts/tree/main/scripts/allagents-setup/cargowise

Before this change, that failed with:

Error: Failed to initialize workspace: Authentication failed for WiseTechGlobal/WTG.AI.Prompts.
  Check your SSH keys or git credentials.

E2E

cd /home/entity/projects/EntityProcess/allagents.worktrees/fix-workspace-init-auth
bun run build
node ./dist/index.js workspace init /tmp/cargowise-allagents-green --from https://github.com/WiseTechGlobal/WTG.AI.Prompts/tree/main/scripts/allagents-setup/cargowise

Verified the workspace initializes successfully and writes /tmp/cargowise-allagents-green/.allagents/workspace.yaml.

Validation

bun run lint
bun test
bun run build

[cloudflare-workers-and-pages]

Deploying allagents with    Cloudflare Pages

Latest commit:	75bc7be
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Branch Preview URL:	https://fix-workspace-init-auth.allagents.pages.dev

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