Remove confirmed dead code from action/api/reducer/component layers

Summary: remove mechanically-confirmed dead code across the frontend while preserving behavior.\n\nScope completed:\n- Removed unreferenced action creators and wrappers in src/actionCreators\n- Removed unreferenced API helpers in src/api\n- Removed dead reducer/action subtree for agreements-with-all-plans\n- Removed zero-inbound component files identified by import-graph scan\n- Removed one component-level unused variable warning\n\nAcceptance criteria:\n- [x] Dead code removed in reviewable slices\n- [x] npm run typecheck passes\n- [x] No remaining zero-inbound component files from this pass\n\nNotes: this task intentionally does not change behavior or tackle broader no-explicit-any cleanup.

Start by reviewing src/actionCreators, src/api, the reducer/action subtree, and component files covered by the import-graph pass; run npm run typecheck. The issue reports dead-code removal and the zero-inbound-component check as complete, so confirm those acceptance criteria before taking it on.

Written by the indexing model from the issue text.