feat: Add shared components, refactor stores, improve data-entry workflow

Shared Components:
- Add CompanySelector.vue and PeriodSelector.vue components
- Add AppHeader.vue and SlideMenu.vue layout components
- Add shared stores factories (companies.js, accountingPeriod.js)
- Add shared routes factories (companies.py, calendar.py)
- Add shared models (company.py, calendar.py)
- Add shared layout styles (header.css, navigation.css)

Data Entry App:
- Update CLAUDE.md with prod/test server documentation
- Improve nomenclature sync service with better error handling
- Update receipts router and CRUD operations
- Add company/period stores using shared factories
- Update App.vue layout with shared components
- Fix OCRUploadZone file handling

Reports App:
- Refactor stores to use shared factories
- Update App.vue to use shared layout components

Infrastructure:
- Replace start-data-entry.sh with separate dev/test scripts
- Add .claude/rules for authentication, backend patterns, etc.
- Add implementation plan for OCR receipt improvements
- Clean up old documentation files

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

shared/frontend/components/layout/AppHeader.vue

@@ -0,0 +1,132 @@
+<template>
+  <header class="header-container" :class="headerClass">
+    <nav class="header-nav">
+      <!-- Left side: Hamburger + Brand -->
+      <div class="header-left">
+        <button
+          class="hamburger-btn"
+          :class="{ active: menuOpen }"
+          @click="$emit('menu-toggle')"
+          aria-label="Toggle navigation menu"
+        >
+          <span class="hamburger-line"></span>
+          <span class="hamburger-line"></span>
+          <span class="hamburger-line"></span>
+        </button>
+        <router-link :to="brandLink" class="header-brand">
+          <slot name="brand">
+            <span>{{ title }}</span>
+          </slot>
+        </router-link>
+      </div>
+
+      <!-- Right side: Period + Company + User -->
+      <div class="header-actions">
+        <PeriodSelector
+          v-if="showPeriod && selectedCompany"
+          :period-store="periodStore"
+          :companies-store="companiesStore"
+          variant="header"
+          @period-changed="onPeriodChanged"
+        />
+        <CompanySelector
+          v-if="showCompany"
+          :companies-store="companiesStore"
+          :show-fiscal-code="true"
+          variant="header"
+          @company-changed="onCompanyChanged"
+        />
+        <slot name="user-menu">
+          <div v-if="showUser && currentUser" class="header-user" @click="$emit('user-menu-toggle')">
+            <i class="pi pi-user"></i>
+            <span class="desktop-only">{{ currentUser?.username || 'User' }}</span>
+          </div>
+        </slot>
+      </div>
+    </nav>
+  </header>
+</template>
+
+<script>
+import { computed } from "vue";
+import CompanySelector from "../CompanySelector.vue";
+import PeriodSelector from "../PeriodSelector.vue";
+
+export default {
+  name: "AppHeader",
+  components: {
+    CompanySelector,
+    PeriodSelector,
+  },
+  props: {
+    // Header title/brand text
+    title: {
+      type: String,
+      default: "ROA2WEB",
+    },
+    // Router link for brand click
+    brandLink: {
+      type: String,
+      default: "/",
+    },
+    // Additional CSS class for header (e.g., 'header-container--gradient')
+    headerClass: {
+      type: String,
+      default: "",
+    },
+    // Is hamburger menu open?
+    menuOpen: {
+      type: Boolean,
+      default: false,
+    },
+    // Companies store instance (required for selectors)
+    companiesStore: {
+      type: Object,
+      required: true,
+    },
+    // Period store instance (required for period selector)
+    periodStore: {
+      type: Object,
+      required: true,
+    },
+    // Current user object for display
+    currentUser: {
+      type: Object,
+      default: null,
+    },
+    // Show/hide period selector
+    showPeriod: {
+      type: Boolean,
+      default: true,
+    },
+    // Show/hide company selector
+    showCompany: {
+      type: Boolean,
+      default: true,
+    },
+    // Show/hide user info
+    showUser: {
+      type: Boolean,
+      default: true,
+    },
+  },
+  emits: ["menu-toggle", "company-changed", "period-changed", "user-menu-toggle"],
+  setup(props, { emit }) {
+    const selectedCompany = computed(() => props.companiesStore.selectedCompany);
+
+    const onCompanyChanged = (company) => {
+      emit("company-changed", company);
+    };
+
+    const onPeriodChanged = (period) => {
+      emit("period-changed", period);
+    };
+
+    return {
+      selectedCompany,
+      onCompanyChanged,
+      onPeriodChanged,
+    };
+  },
+};
+</script>