Plan RIMS migration to Angular 21, Express 5, TypeScript, SQLite, and Drizzle

[fusion94]

Description

RIMS should align with the current standard DamageLabs stack so it can serve as the real shared core for future products.

This issue is for planning the migration or rebuild path into:

• Angular 21
• Express 5
• TypeScript
• SQLite
• Drizzle ORM

The goal is not to rebuild blindly, but to define an intentional path from the current implementation to the target architecture.

Acceptance Criteria

• Document the current RIMS stack and architecture
• Document the target stack and why it is the target
• Identify major migration risks and unknowns
• Propose whether RIMS should be incrementally migrated or cleanly rebuilt
• Define major migration phases
• Produce an implementation roadmap for the stack transition