refactor(frontend): comprehensive split of large view files into modular components

- Split UsersView.vue into UserCreateModal, UserEditModal, UserApiKeysModal, etc.
- Split UsageView.vue into UsageStatsCards, UsageFilters, UsageTable, etc.
- Split DashboardView.vue into UserDashboardStats, UserDashboardCharts, etc.
- Split AccountsView.vue into AccountTableActions, AccountTableFilters, etc.
- Standardized TypeScript types across new components to resolve implicit 'any' and 'never[]' errors.
- Improved overall frontend maintainability and code clarity.

frontend/src/components/common/TextArea.vue

@@ -0,0 +1,81 @@
+<template>
+  <div class="w-full">
+    <label v-if="label" :for="id" class="input-label mb-1.5 block">
+      {{ label }}
+      <span v-if="required" class="text-red-500">*</span>
+    </label>
+    <div class="relative">
+      <textarea
+        :id="id"
+        ref="textAreaRef"
+        :value="modelValue"
+        :disabled="disabled"
+        :required="required"
+        :placeholder="placeholderText"
+        :readonly="readonly"
+        :rows="rows"
+        :class="[
+          'input w-full min-h-[80px] transition-all duration-200 resize-y',
+          error ? 'input-error ring-2 ring-red-500/20' : '',
+          disabled ? 'cursor-not-allowed bg-gray-100 opacity-60 dark:bg-dark-900' : ''
+        ]"
+        @input="onInput"
+        @change="$emit('change', ($event.target as HTMLTextAreaElement).value)"
+        @blur="$emit('blur', $event)"
+        @focus="$emit('focus', $event)"
+      ></textarea>
+    </div>
+    <!-- Hint / Error Text -->
+    <p v-if="error" class="input-error-text mt-1.5">
+      {{ error }}
+    </p>
+    <p v-else-if="hint" class="input-hint mt-1.5">
+      {{ hint }}
+    </p>
+  </div>
+</template>
+
+<script setup lang="ts">
+import { computed, ref } from 'vue'
+
+interface Props {
+  modelValue: string | null | undefined
+  label?: string
+  placeholder?: string
+  disabled?: boolean
+  required?: boolean
+  readonly?: boolean
+  error?: string
+  hint?: string
+  id?: string
+  rows?: number | string
+}
+
+const props = withDefaults(defineProps<Props>(), {
+  disabled: false,
+  required: false,
+  readonly: false,
+  rows: 3
+})
+
+const emit = defineEmits<{
+  (e: 'update:modelValue', value: string): void
+  (e: 'change', value: string): void
+  (e: 'blur', event: FocusEvent): void
+  (e: 'focus', event: FocusEvent): void
+}>()
+
+const textAreaRef = ref<HTMLTextAreaElement | null>(null)
+const placeholderText = computed(() => props.placeholder || '')
+
+const onInput = (event: Event) => {
+  const value = (event.target as HTMLTextAreaElement).value
+  emit('update:modelValue', value)
+}
+
+// Expose focus method
+defineExpose({
+  focus: () => textAreaRef.value?.focus(),
+  select: () => textAreaRef.value?.select()
+})
+</script>