Add comprehensive architecture improvement backlog

Document catalogs identified architectural issues, technical debt, and
improvement opportunities based on deep-dive analysis of the codebase.
Includes critical logic bugs, silent error handling issues, API
inconsistencies, hardcoded values, and large file candidates for
refactoring.

Key findings:
- 8 critical logic/correctness issues identified
- 12 silent error handling problems
- 24 source files over 500 lines
- Prioritized roadmap for remediation

Ref: EC-1726

Signed-off-by: Rob Nester <rnester@redhat.com>
Assisted-by: Cursor
Made-with: Cursor

Author: robnester-rh