feat(inbox): configurable base branch for inbox auto-PRs

[tatoalo]

Summary

adding configurable base branch for auto-PRs setting so inbox-driven cloud tasks can target a chosen branch (renderer side of #2470)

[greptile-apps]

Prompt To Fix All With AI

Fix the following 1 code review issue. Work through them one at a time, proposing concise fixes.

---

### Issue 1 of 1
apps/code/src/renderer/features/inbox/hooks/useCreatePrReport.ts:107-111
The two-step lookup normalises only the *lookup* key, not the *stored* key. If the map entry was stored with uppercase letters (e.g. `MyOrg/MyRepo`) and `cloudRepository` arrives in lowercase, both lookups miss and the PR silently falls back to the repo default. Storing and looking up with a single canonical form (e.g. always `toLowerCase()`) would make the behaviour unambiguous. The current fallback is safe but the asymmetry could cause a confusing "setting has no effect" situation if casing diverges between the UI's source and the report's `cloudRepository`.

```suggestion
    const baseBranchOverrides = autonomyConfig?.autostart_base_branches ?? {};
    const baseBranch =
      baseBranchOverrides[cloudRepository] ??
      baseBranchOverrides[cloudRepository.toLowerCase()] ??
      baseBranchOverrides[
        Object.keys(baseBranchOverrides).find(
          (k) => k.toLowerCase() === cloudRepository.toLowerCase(),
        ) ?? ""
      ] ??
      null;
```

_{Reviews (1): Last reviewed commit: "feat(inbox): configurable base branch fo..." | Re-trigger Greptile}

[github-actions]

React Doctor found no issues in the changed files. 🎉

_{Reviewed by React Doctor for commit 48d86da.}