Fix GitHub App token scope for internal repository access

The workflow was failing because the GitHub App token generated by
actions/create-github-app-token@v1 was only scoped to the current
repository (kernel-src-tree) by default. When it tried to checkout
kernel-container-build (which has INTERNAL visibility), the token
didn't have access, resulting in "Repository not found" errors.

Added explicit repositories parameter to all token generation steps
to grant access to all required repositories:
- kernel-tools
- kernel-src-tree
- kernel-src-tree-tools
- kernel-container-build

This fix applies to all 5 token generation steps in the workflow:
- build job
- boot job
- test-kselftest job
- compare-results job
- create-pr job

Fixes: https://github.com/ctrliq/kernel-src-tree/actions/runs/19970287958

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude <noreply@anthropic.com>

Author: tylergohl