feat(0): add createBreadcrumbs composable

Lightweight breadcrumb navigation composable with:
- Path manipulation (push, pop, select, replace)
- Navigation methods (first, prev)
- Automatic collapse with ellipsis for long paths
- v-model support via ref passthrough
- Trinity pattern for dependency injection

Includes documentation page and 37 tests.

Author: johnleider

.claude/rules/components.md

@@ -95,3 +95,24 @@ export * from './SelectionRoot.vue'
 export type { SelectionRootProps, SelectionRootSlotProps } from './SelectionRoot.vue'
 export { default as SelectionRoot } from './SelectionRoot.vue'
 ```
+
+## Z-Index and Layering
+
+When implementing z-index or layering changes:
+
+1. **Verify stacking context** by testing visually in browser
+2. **Overlays must appear above content** they're meant to cover, not behind
+3. **Check parent stacking contexts** — a high z-index inside a low context won't escape
+4. **Document z-index values** used in component comments
+
+**Common issues:**
+- Scrim appearing over dialog content instead of behind
+- Popovers clipped by overflow:hidden parents
+- Multiple overlays fighting for top layer
+
+**Verification checklist for overlay components:**
+- [ ] Overlay covers intended content
+- [ ] Scrim appears behind modal content
+- [ ] Focus trap works correctly
+- [ ] Escape key dismisses in correct order
+- [ ] Nested overlays stack correctly

apps/docs/src/pages/composables/utilities/create-breadcrumbs.md

@@ -0,0 +1,65 @@
+---
+title: createBreadcrumbs - Lightweight Path Navigation for Vue 3
+meta:
+- name: description
+  content: Lightweight composable for breadcrumb navigation state. Includes path manipulation methods (push, pop, select), computed visible items with collapse, and v-model binding for Vue 3.
+- name: keywords
+  content: createBreadcrumbs, breadcrumbs, navigation, composable, Vue 3, path, trail, hierarchy
+features:
+  category: Composable
+  label: 'E: createBreadcrumbs'
+  github: /composables/createBreadcrumbs/
+  level: 2
+related:
+  - /composables/utilities/create-pagination
+---
+
+# createBreadcrumbs
+
+A composable for managing breadcrumb navigation state with path manipulation methods and automatic collapse of middle items when paths get long.
+
+<DocsPageFeatures :frontmatter />
+
+## Usage
+
+The `createBreadcrumbs` composable provides reactive breadcrumb state management with navigation methods and automatic computation of visible items with ellipsis support for long paths.
+
+```ts collapse
+import { createBreadcrumbs } from '@vuetify/v0'
+
+const breadcrumbs = createBreadcrumbs({ visible: 4 })
+
+breadcrumbs.register({ text: 'Home' })
+breadcrumbs.register({ text: 'Products' })
+breadcrumbs.register({ text: 'Electronics' })
+breadcrumbs.register({ text: 'Phones' })
+breadcrumbs.register({ text: 'iPhone' })
+
+console.log(breadcrumbs.tickets.value)
+// [
+//   { type: 'crumb', value: { text: 'Home', ... }, index: 0 },
+//   { type: 'ellipsis', value: '…', collapsed: [...] },
+//   { type: 'crumb', value: { text: 'Phones', ... }, index: 3 },
+//   { type: 'crumb', value: { text: 'iPhone', ... }, index: 4 }
+// ]
+
+// Navigate back
+breadcrumbs.prev()  // removes iPhone, selects Phones
+breadcrumbs.first() // truncates to Home
+```
+
+## Architecture
+
+`createBreadcrumbs` manages a path array with automatic collapse:
+
+```mermaid "Breadcrumbs Flow"
+flowchart LR
+  items --> depth
+  items --> tickets[visible tickets]
+  visible --> tickets
+  ellipsis --> tickets
+  depth --> isRoot
+  depth --> isEmpty
+```
+
+<DocsApi />

apps/docs/src/typed-router.d.ts

@@ -415,6 +415,13 @@ declare module 'vue-router/auto-routes' {
       Record<never, never>,
       | never
     >,
+    '/composables/utilities/create-breadcrumbs': RouteRecordInfo<
+      '/composables/utilities/create-breadcrumbs',
+      '/composables/utilities/create-breadcrumbs',
+      Record<never, never>,
+      Record<never, never>,
+      | never
+    >,
     '/composables/utilities/create-filter': RouteRecordInfo<
       '/composables/utilities/create-filter',
       '/composables/utilities/create-filter',
@@ -1009,6 +1016,12 @@ declare module 'vue-router/auto-routes' {
       views:
         | never
     }
+    'src/pages/composables/utilities/create-breadcrumbs.md': {
+      routes:
+        | '/composables/utilities/create-breadcrumbs'
+      views:
+        | never
+    }
     'src/pages/composables/utilities/create-filter.md': {
       routes:
         | '/composables/utilities/create-filter'