refactor(breadcrumbs): extract callback route renderers into mapped groups

memory-bank/change-log.md

@@ -668,6 +668,47 @@ Follow-ups:
 
 - Next larger slice: extract remaining callback-bearing deterministic branches into mapped route groups with callback injection, then update structure guards accordingly.
 
+### CL-22541-V: breadcrumbs larger slice — callback route-group extraction (`/myportal/case/id/[incident]`, `/case`)
+
+date: 2026-04-09  
+author: Cline  
+scope: `lib/routing/{breadcrumbRendererFactories,breadcrumbRouteMaps}.js`, `components/breadcrumbs.js`, `tests/phase22/{breadcrumb-route-maps-helper,breadcrumbs-route-map-structure}.test.cjs`  
+type: change  
+rationale: Execute the next larger extraction slice by moving callback-bearing breadcrumb branches into a dedicated callback renderer map while preserving `router.back()` behavior through explicit callback injection.
+impact: Structural refactor with preserved callback semantics; no intended route/auth/session/API/EN-CY/a11y behavior change.
+status: completed
+
+Summary:
+
+- Added `createCallbackRouteRenderers(...)` in `lib/routing/breadcrumbRendererFactories.js` to map:
+    - `/myportal/case/id/[incident]`
+    - `/case`
+- Introduced explicit callback injection (`onBack`) into grouped factory composition and route renderers, preserving `router.back()` behavior via injected callback.
+- Extended `createMappedRouteRendererGroups(...)` return with `callbackRouteRenderersByPath`.
+- Updated map builder in `lib/routing/breadcrumbRouteMaps.js` to include callback map in explicit precedence order:
+    - simple -> link-text -> myportal -> new-appeal -> callback -> case detail -> detail/account.
+- Updated `components/breadcrumbs.js`:
+    - pass `onBack: () => { router.back(); }` into grouped factory composition
+    - include callback route map in `buildBreadcrumbRendererMaps(...)`
+    - remove now-redundant inline `isPath("/myportal/case/id/[incident]")` and `isPath("/case")` branches.
+- Expanded tests:
+    - `tests/phase22/breadcrumb-route-maps-helper.test.cjs`
+        - update grouped map order assertions to seven maps including callback group.
+    - `tests/phase22/breadcrumbs-route-map-structure.test.cjs`
+        - assert callback factory export and mapped callback route presence
+        - assert callback map inclusion in component grouped destructuring and map-order invariant
+        - assert inline callback branches are removed while `router.back();` remains preserved.
+
+Validation:
+
+- `npx eslint lib/routing/breadcrumbRendererFactories.js lib/routing/breadcrumbRouteMaps.js components/breadcrumbs.js tests/phase22/breadcrumb-route-maps-helper.test.cjs tests/phase22/breadcrumbs-route-map-structure.test.cjs tests/phase22/index.test.cjs` -> pass.
+- `node tests/phase22/index.test.cjs` -> pass (combined suite).
+
+Follow-ups:
+
+- Next smaller slice candidate: add a focused helper test for empty-string/whitespace path lookups to assert strict null behavior for non-exact keys.
+- Next larger slice candidate: evaluate whether `/newappeal/[appealtypes]` and `/myportal/[appealtypes]` back-link branches can be extracted with explicit callback/setter injection while preserving state-step semantics.
+
 ### CL-00X: 22500 `components/elements/index.js` Phase 1 helper extraction
 
 date: 2026-04-07