Expand frontend coverage with a 40/60/80 ratchet

[JavierGOrdonnez]

Scope

Raise frontend unit/component coverage in documented stages.

• Establish and record the current baseline.
• Ratchet the target to 40%, then 60%, then 80%.
• Prioritize high-risk UI behavior and user workflows.
• Keep the initial Codecov threshold informational until the baseline and report paths are stable.

Acceptance criteria

• Each ratchet stage has a measurable threshold and owner/checklist.
• CI reports the threshold and prevents accidental regression once the stage is adopted.
• Coverage exclusions are explicit and justified.
• The final 80% target is enforced or has a documented reason for any remaining exception.