docs(migration): update v3 guide

docs/content/docs/1.getting-started/3.migration/2.v3.md

@@ -399,6 +399,204 @@ This change affects the following components: `Modal`, `Slideover`.
 + <USelectMenu v-model="country" :items="countries" @update:modelValue="console.log(newVal)" />
 ```
 
+#### Accordion
+The `Accordion` component has been hugely redesigned to provide a clearer state model, improved accessibility, and more flexible customization. As a result, its API is not fullybackward compatible.
+
+Below are the most important changes to migrate existing usage.
+
+- The `multiple` prop has been replaced by the `type` prop:
+
+```diff
+<template>
+- <UAccordion multiple :items="items" />
++ <UAccordion type="multiple" :items="items" />
+</template>
+```
+When omitted, `type` defaults to `single`.
+
+- The `default-open` prop and `defaultOpen` **item** property have been removed.
+
+Accordion state is now controlled using default-value (uncontrolled) or v-model (controlled):
+
+```diff
+<template>
+- <UAccordion default-open multiple :items="items" />
++ <UAccordion
++   type="multiple"
++   :default-value="['0', '1']"
++   :items="items"
++ />
+</template>
+```
+
+- The slot API has been simplified and made more explicit.
+The `#item` slot has been removed in favor of `#content` and `#body`:
+
+```diff
+<template>
+- <template #item="{ item }">
+-   {{ item.content }}
+- </template>
+
++ <template #content="{ item }">
++   {{ item.content }}
++ </template>
+</template>
+```
+
+::note
+The default slot now only customizes the trigger, with additional slots for finer control (`#leading`, `#trailing`, `#body`).
+::
+
+::note
+The Accordion now follows a controlled / uncontrolled pattern (v-model / default-value) and introduces a more structured slot and styling system.
+Refer to the Accordion documentation for full details and advanced use cases.
+::
+
+
+#### Table
+The `Table` component had a major redesign, as it now uses the [TanStack Table](https://tanstack.com/table/latest){target="_blank" rel="noopener"} under the hood. This resulted in an almost new API and some breaking changes, but with many great features along the way. 
+
+Below are the most important changes to migrate existing usage.
+
+- The `rows` prop has been renamed in favbor of `data`:
+
+```diff
+<template>
+- <UTable :rows="items" :columns="headers" />
++ <UTable :data="items" :columns="headers" />
+</template>
+```
+
+- Columns definition is now explicit & semantic:
+
+```diff
+<script setup lang="ts">
+- const headers = {
+-  label: 'Status',
+-  key: 'status'
+- }
++ const headers = [
++   {
++     header: 'Status',
++     accessorKey: 'status'
++   }
++ ]
+</script>
+```
+
+- Row cell slot names has been changed from `<column-accessorKey>-data` to `<column-accessorKey>-cell`:
+
+```diff
+<template>
+- <template #column-data="{ row }">
++ <template #column-cell="{ row }">
+</template>
+```
+
+- Slots receive a row wrapper, not the raw object, augmented with differnet properties:
+
+```diff
+<template>
+- row.status
++ row.original.status
+</template>
+```
+
+::note
+Every slot using row.xxx must switch to row.original.xxx
+::
+
+::note
+Those are only some of the many breaking changes, refer to the Table documentation for full details and advanced use cases.
+::
+
+
+#### Tabs
+
+- The `#item` slot has been removed in favor of `#content`
+
+```diff
+<template>
+- <template #item="{ item }">
++ <template #content="{ item }">
+</template>
+```
+
+::note
+There are now other slots including `leading`, `trailing`, `list-leading` and `list-trailing`. Kindly refers to the Tabs documentation for full details and examples
+::
+
+- The prop `defaultIndex` has been removed in favor of `defaultValue` that takes the new `value` prop in `items[]`, that v-model now binds to it.
+
+```diff
+<template>
+- <UTabs :default-index="0" :items="tabs" />   
++ <UTabs :default-value="0" :items="tabs" />
+</template>
+```
+
+::note
+The `value?` prop could be `string` | `number` and it's a unique value for the tab item. Defaults to the index.
+::
+
+- The prop `unmount` has been removed in favor of `unmountOnHide`, that's when set to `true`, the element will be unmounted on closed state.
+Defaults to `true`.
+
+```diff
+<template>
+- <UTabs umount :items="tabs" />   
++ <UTabs :unmount-on-hide="true" :items="tabs" />
+</template>
+```
+
+#### Alert
+
+- The `close-button` prop has been replaced by the `close` prop:
+```diff
+<template>
+- <UAlert :close-button="{ icon: 'i-heroicons-x-mark', variant: 'link' }" />
++ <UAlert :close="{ icon: 'i-lucide-x', variant: 'link' }" />
+</template>
+```
+
+- The `close` event has been replaced by the `update:open` event:
+
+```diff
+<template>
+- <UAlert @close="isOpen = false" />
++ <UAlert @update:open="isOpen = false" />
+</template>
+```
+
+- The `#icon` and `#avatar` slots have been replaced by a single `#leading` slot:
+
+```diff
+<template>
+- <UAlert>
+-   <template #icon>
+-     <UIcon name="i-heroicons-command-line" />
+-   </template>
+- </UAlert>
+
++ <UAlert>
++   <template #leading>
++     <UIcon name="i-lucide-terminal" />
++   </template>
++ </UAlert>
+</template>
+```
+
+
+- `Form` now always validates on submit, as a result the `validate-on` prop only controls which input events triggers validation, that besides the default form validation on submit, so if you want the `Form` to validate only on sibmit, you need to pass an empty array to `validate-on`
+
+```diff
+<template></template>
+- <UForm :validate-on="['submit']" /> 
++ <UForm :validate-on="[]" />
+</template>
+```
+
 ### Changed composables
 
 - The `useToast()` composable `timeout` prop has been renamed to `duration`: