Multi‑repo / org‑level analysis and cross‑repo insights

[Joexiaohongchen]

Description
Goal: Enable analysis across multiple repositories or an entire org.

Scope:

• Add UI to select multiple repos (from user/org list).
• Aggregate context (README + key files) across repos.
• Provide cross‑repo insights: shared dependencies, duplicated modules, security hotspots.
• Add summary report view and export.

Acceptance criteria:

• User can pick >1 repo and run a combined analysis.
• Results include cross‑repo summary + per‑repo drill‑downs.
• Performance guardrails (max repos, file caps).

Notes:

• Consider a “Quick vs Deep” mode for aggregated scans.