react-doctor rung 1: no-giant-component

[radandevist]

Parent: #1291 (rung 1 of 3 of the re-enable ladder)

Scope

Split every component over the 300-line threshold in apps/front/src (16 findings / 16 files measured 2026-08-24 on the then-current tree, see the rung-0 measurement comment on the parent), then re-enable react-doctor/no-giant-component by removing its single off line from apps/front/doctor.config.json.

Acceptance

• Full-tree react-doctor@0.9.12 scan at default severity: zero no-giant-component findings
• Rule proven to actually run: a planted >300-line canary fires before removal
• Front unit/component suite + typecheck green (heavy.sh serialized)
• Local CI replica green: --scope files --base origin/develop --blocking warning
• doctor.config.json diff minimal: exactly one line removed