feat: add Calendar, Timesheet, and MiniTimer views

Calendar shows weekly time-block layout with hour rows, entry positioning,
current time indicator, and week navigation. Timesheet provides a weekly
grid with project/task rows, day columns, totals, and add-row functionality.
MiniTimer is a minimal always-on-top timer display for the floating window.

src/views/MiniTimer.vue

@@ -0,0 +1,27 @@
+<template>
+  <div class="mini-timer flex items-center justify-center h-screen bg-bg-base select-none" style="-webkit-app-region: drag">
+    <div class="text-center">
+      <p class="text-[2rem] font-medium font-[family-name:var(--font-heading)] tracking-tighter text-text-primary">
+        {{ timerStore.formattedTime }}
+      </p>
+      <p v-if="projectName" class="text-[0.6875rem] text-text-tertiary mt-1 truncate max-w-[180px]">
+        {{ projectName }}
+      </p>
+    </div>
+  </div>
+</template>
+
+<script setup lang="ts">
+import { computed } from 'vue'
+import { useTimerStore } from '../stores/timer'
+import { useProjectsStore } from '../stores/projects'
+
+const timerStore = useTimerStore()
+const projectsStore = useProjectsStore()
+
+const projectName = computed(() => {
+  if (!timerStore.selectedProjectId) return ''
+  const project = projectsStore.projects.find(p => p.id === timerStore.selectedProjectId)
+  return project?.name || ''
+})
+</script>