Implement store reset methods to enable router-based login/logout

## Context

Currently, the application uses `window.location.reload()` on logout because `router.push()` doesn't invalidate all app state, which causes issues when changing accounts.

## Problem

When using `router.push()` for logout, state persists across account changes. For example, `isSettingsReady` remains true, causing new users to inherit previous users' cached settings.

## Desired Outcome

Implement proper store reset methods in `bootstrapStore` and `settingStore` (and any other stores that need cleanup) so that logout can use `router.push()` instead of `window.location.reload()`.

## References

- PR: https://github.com/Comfy-Org/ComfyUI_frontend/pull/8307
- Discussion: https://github.com/Comfy-Org/ComfyUI_frontend/pull/8307#discussion_r2729390263
- Requester: @DrJKL

## Affected Files

- `src/stores/bootstrapStore.ts` - needs reset method
- `src/platform/settings/settingStore.ts` - needs reset method
- `SidebarLogoutIcon.vue` - should use router.push() after stores have reset capabilities
- Other stores may also need reset methods for complete state cleanup

┆Issue is synchronized with this [Notion page](https://www.notion.so/Issue-8337-Implement-store-reset-methods-to-enable-router-based-login-logout-2f56d73d3650818cb38dfeee839b86ca) by [Unito](https://www.unito.io)