chore(repo): rename external repository and local checkout from codex to strata

[alucero270]

chore(repo): rename external repository and local checkout from codex to strata

Summary

Normalize the external repository name and the primary local checkout path so the product-facing Strata identity is reflected in both GitHub and the default local workspace.

Scope

• GitHub repository slug
• local origin remote URL
• local checkout folder name

Acceptance Criteria

• the GitHub repository is renamed from codex to strata
• the local checkout remote points at the new repository URL
• the local checkout folder is renamed from codex to strata
• the rename does not lose access to the existing branches or open pull requests

Notes

• This is an administrative rename task, not an internal code-identifier rename
• Internal Codex.* identifiers remain transitional follow-up work