Adds first version of the app. Local storage only.

src/data/LocalStorageProjectRepository.ts

@@ -0,0 +1,26 @@
+import type { Project } from '../domain/types'
+import { normalizeProject } from './exportImport'
+import type { ProjectRepository } from './ProjectRepository'
+
+const STORAGE_KEY = 'av-planner:project:v1'
+
+export class LocalStorageProjectRepository implements ProjectRepository {
+  async load(): Promise<Project | null> {
+    try {
+      const raw = window.localStorage.getItem(STORAGE_KEY)
+      if (!raw) return null
+      return normalizeProject(JSON.parse(raw) as Project)
+    } catch (err) {
+      console.error('Failed to load project from localStorage', err)
+      return null
+    }
+  }
+
+  async save(project: Project): Promise<void> {
+    window.localStorage.setItem(STORAGE_KEY, JSON.stringify(project))
+  }
+
+  async clear(): Promise<void> {
+    window.localStorage.removeItem(STORAGE_KEY)
+  }
+}

src/data/ProjectRepository.ts

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+import type { Project } from '../domain/types'
+
+/**
+ * Storage abstraction the rest of the app codes against. Today only
+ * `LocalStorageProjectRepository` implements it; a future backend would add
+ * e.g. `ApiProjectRepository` (REST/GraphQL) behind this same interface so
+ * the store/UI layers wouldn't need to change.
+ */
+export interface ProjectRepository {
+  load(): Promise<Project | null>
+  save(project: Project): Promise<void>
+  clear(): Promise<void>
+}

src/data/exportImport.ts

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+import type { Project } from '../domain/types'
+
+export function projectToJson(project: Project): string {
+  return JSON.stringify(project, null, 2)
+}
+
+export function downloadProjectFile(project: Project): void {
+  const json = projectToJson(project)
+  const blob = new Blob([json], { type: 'application/json' })
+  const url = URL.createObjectURL(blob)
+  const a = document.createElement('a')
+  const safeName = project.name.trim().replace(/[^a-z0-9-_]+/gi, '_') || 'project'
+  a.href = url
+  a.download = `${safeName}.avplan.json`
+  document.body.appendChild(a)
+  a.click()
+  a.remove()
+  URL.revokeObjectURL(url)
+}
+
+class ProjectImportError extends Error {}
+
+/** Minimal structural check — enough to catch "wrong file" without pulling
+ *  in a schema validation library for a single call site. */
+function assertLooksLikeProject(value: unknown): asserts value is Project {
+  if (typeof value !== 'object' || value === null) {
+    throw new ProjectImportError('File does not contain a JSON object.')
+  }
+  const p = value as Partial<Project>
+  if (typeof p.id !== 'string' || typeof p.name !== 'string') {
+    throw new ProjectImportError('File is missing required project fields.')
+  }
+  if (!Array.isArray(p.devices) || !Array.isArray(p.connections)) {
+    throw new ProjectImportError('File is missing devices/connections arrays.')
+  }
+}
+
+export async function readProjectFile(file: File): Promise<Project> {
+  const text = await file.text()
+  let parsed: unknown
+  try {
+    parsed = JSON.parse(text)
+  } catch {
+    throw new ProjectImportError('File is not valid JSON.')
+  }
+  assertLooksLikeProject(parsed)
+  return normalizeProject(parsed)
+}
+
+/** Fills in collections added after a project may have been saved/exported,
+ *  so older data (from localStorage or an older export file) doesn't crash
+ *  code that expects these arrays to always exist. */
+export function normalizeProject(project: Project): Project {
+  return {
+    ...project,
+    customDeviceTemplates: project.customDeviceTemplates ?? [],
+    customPortTypes: project.customPortTypes ?? [],
+    customCableTypes: project.customCableTypes ?? [],
+    customDeviceCategories: project.customDeviceCategories ?? [],
+    hiddenBuiltInDeviceTemplateIds: project.hiddenBuiltInDeviceTemplateIds ?? [],
+  }
+}
+
+export { ProjectImportError }