Cloud routines/sessions cannot access private repos on a personal GitHub account (403 permission_error)

## Description
Scheduled cloud routines (POST /v1/code/triggers) and cloud sessions reject any source repo that is a **private repository on the user's personal GitHub account**, returning HTTP 403 `{"message":"You don't have access to a repository this routine uses","resource":"ccr_trigger","type":"permission_error"}`.

## Setup
- claude.ai account with GitHub connected; org repos (via org installation) work fine in routines and cloud sessions.
- Personal account: installed the Claude GitHub app with "Only select repositories" including the private repo, saved, and reconnected the GitHub integration on claude.ai.
- Cloud session repo listing shows the org's repos and the personal account's **public** repo, but the personal **private** repo never appears; `add_repo` also reports no access.

## Expected
After installing the app on the personal account and selecting the private repo, routines/cloud sessions should be able to clone it — or the docs/UI should state that personal private repos aren't supported alongside an org grant and offer a re-auth path that covers both.

## Impact
Users can't point routines at a personal private notes/config repo while keeping org access. No workaround without org repo-creation rights.

🤖 Filed via Claude Code on the user's behalf

Reproduce with the described GitHub-connected claude.ai account, using a personal private repository alongside an organization repository. Check POST /v1/code/triggers, cloud-session repository listing, and add_repo for the reported 403 and missing repository. Done means the personal private repository works, or the docs/UI clearly explain the limitation and provide an appropriate re-authentication path.

Scritto dal modello di indicizzazione a partire dal testo della issue.