# Feature Specification: Integrate SvelteKit

**Feature Branch**: `004-integrate-svelte-kit`  
**Created**: 2025-12-20  
**Status**: Draft  
**Input**: User description: "Integrate SvelteKit into the project"

## User Scenarios & Testing *(mandatory)*

### User Story 1 - Seamless Navigation (Priority: P1)

As a user, I want to navigate between different parts of the application (Dashboard, Settings) using standard URL paths so that I can bookmark pages and use the browser's back/forward buttons reliably.

**Why this priority**: Core application usability and standard web behavior.

**Independent Test**: Can be tested by clicking navigation links and verifying the URL changes and the correct content renders without a full page reload.

**Acceptance Scenarios**:

1. **Given** I am on the Dashboard, **When** I click the "Settings" link, **Then** the URL changes to `/settings` and the Settings page is displayed.
2. **Given** I am on `/settings`, **When** I refresh the page, **Then** the Settings page is still displayed (not redirected to home).

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### User Story 2 - Improved Data Loading (Priority: P2)

As a developer, I want to use modern data loading patterns so that data is fetched efficiently before the page renders, reducing layout shifts and loading spinners.

**Why this priority**: Improves user experience and developer productivity.

**Independent Test**: Can be tested by observing the page load sequence and verifying that data is available to the component immediately upon mount.

**Acceptance Scenarios**:

1. **Given** a page requires data from the backend, **When** the page is navigated to, **Then** the data is fetched and ready before the content is fully visible.

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### User Story 3 - Unified Layout (Priority: P3)

As a user, I want a consistent look and feel across all pages with a shared navigation bar and footer.

**Why this priority**: Visual consistency and ease of use.

**Independent Test**: Can be tested by navigating between pages and verifying that the header/footer remain static and do not re-render or flicker.

**Acceptance Scenarios**:

1. **Given** I am navigating between Dashboard and Settings, **When** the page changes, **Then** the top navigation bar remains visible and unchanged.

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### Edge Cases

- **Invalid Routes**: When a user navigates to a non-existent URL, the system should display a user-friendly 404 error page with a link back to the dashboard.
- **API Failures during Load**: If the backend API is unavailable during a data load operation, the system should display a graceful error message or redirect to a dedicated error page.

## Requirements *(mandatory)*

### Functional Requirements

- **FR-001**: System MUST use SvelteKit as the primary frontend framework.
- **FR-002**: System MUST implement file-based routing for all existing pages (Dashboard, Settings).
- **FR-003**: System MUST be deployable as a Static Single Page Application (SPA) to be served by the existing backend.
- **FR-004**: System MUST provide a shared layout mechanism for common UI elements (header, footer).
- **FR-005**: System MUST handle client-side navigation between routes without full page refreshes.
- **FR-006**: System MUST integrate with the existing backend API for data retrieval.
- **FR-007**: System MUST support data submission via existing API endpoints using standard asynchronous requests.

### Key Entities *(include if feature involves data)*

- **Route**: Represents a URL path and its associated page content and data requirements.
- **Layout**: Represents a shared UI structure that wraps multiple routes.

## Success Criteria *(mandatory)*

### Measurable Outcomes

- **SC-001**: Page transition time between Dashboard and Settings is under 200ms.
- **SC-002**: 100% of existing frontend functionality is preserved after migration.
- **SC-003**: Application is accessible via direct URLs (e.g., `/settings`) without manual configuration of the web server for SPA routing.
- **SC-004**: Developer setup time for the frontend is reduced by using standard framework tooling.

## Assumptions

- The application will be deployed as a static site served by the Python backend (no Node.js server in production).
- Existing API endpoints are sufficient for the frontend needs.