Initial commit: habit tracker PWA with Google OAuth, push notifications

FastAPI + SQLAlchemy/Alembic + MariaDB backend with Jinja2/htmx/Alpine
server-rendered frontend. Multi-user via Google OAuth, daily habit
tracking, monthly/weekly history views, Web Push reminders via
APScheduler, and PWA support (manifest, service worker, offline caching).

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>

app/templates/partials/_weekday_alarm_fields.html

@@ -0,0 +1,28 @@
+<div class="field">
+  <label>시행 요일</label>
+  <div class="weekday-picker">
+    <template x-for="(day, idx) in days" :key="idx">
+      <button
+        type="button"
+        class="weekday-pill"
+        :class="{ selected: (mask & (1 << idx)) !== 0 }"
+        @click="if (mask !== (1 << idx)) mask = mask ^ (1 << idx)"
+        x-text="day"
+      ></button>
+    </template>
+    <button
+      type="button"
+      class="everyday-btn"
+      :class="{ selected: mask === 127 }"
+      @click="mask = 127"
+    >매일</button>
+  </div>
+</div>
+
+<div class="field">
+  <label style="display:flex; align-items:center; gap:8px;">
+    <input type="checkbox" x-model="alarmOn" style="width:auto;" />
+    알람 사용
+  </label>
+  <input x-show="alarmOn" x-cloak type="time" name="reminder_time" value="{{ reminder_value|default('') }}" style="margin-top:6px;" />
+</div>