feat(logs): date filter + clear log endpoints

- API GET /api/logs now accepts from_ts / to_ts (unix epoch, half-open
  [from, to)) so callers can scope by arbitrary time range.
- API DELETE /api/logs added. Same from_ts / to_ts semantics. No params
  = wipe everything and reset the AUTOINCREMENT counter.
- Dashboard Logs page: date picker that scopes both the view and the
  delete button to the selected day in the user's local timezone. The
  clear button is red and confirms before deleting; label switches
  between "전체 로그 초기화" and "<날짜> 하루치 삭제".

frontend/src/api.js

@@ -32,5 +32,11 @@ export const api = {
     ).toString()
     return req('/logs' + (q ? `?${q}` : ''))
   },
+  clearLogs: (params = {}) => {
+    const q = new URLSearchParams(
+      Object.fromEntries(Object.entries(params).filter(([, v]) => v !== '' && v != null))
+    ).toString()
+    return req('/logs' + (q ? `?${q}` : ''), { method: 'DELETE' })
+  },
   restart: () => req('/proxy/restart', { method: 'POST' }),
 }

frontend/src/pages/Logs.jsx

@@ -5,16 +5,33 @@ function fmtTime(ts) {
   return new Date(ts * 1000).toLocaleString('ko-KR')
 }
 
+// 'YYYY-MM-DD' 문자열을 로컬 자정 unix epoch (초) 로 바꾼다.
+function dayStart(dateStr) {
+  if (!dateStr) return null
+  const [y, m, d] = dateStr.split('-').map((s) => parseInt(s, 10))
+  return new Date(y, m - 1, d, 0, 0, 0, 0).getTime() / 1000
+}
+function dayEnd(dateStr) {
+  const start = dayStart(dateStr)
+  return start == null ? null : start + 86400
+}
+
 export default function Logs() {
   const [data, setData] = useState({ total: 0, items: [] })
   const [filter, setFilter] = useState('')
+  const [date, setDate] = useState('')
   const [auto, setAuto] = useState(true)
   const [error, setError] = useState(null)
+  const [msg, setMsg] = useState(null)
 
   async function load() {
     try {
       const params = { limit: 100 }
       if (filter) params.action = filter
+      if (date) {
+        params.from_ts = dayStart(date)
+        params.to_ts = dayEnd(date)
+      }
       setData(await api.logs(params))
       setError(null)
     } catch (e) {
@@ -27,7 +44,30 @@ export default function Logs() {
     if (!auto) return
     const id = setInterval(load, 3000)
     return () => clearInterval(id)
-  }, [filter, auto])
+  }, [filter, date, auto])
+
+  async function clearLogs() {
+    const scope = date ? `${date} 하루치` : '전체'
+    if (!window.confirm(`${scope} 접속 로그를 정말 삭제할까요? (되돌릴 수 없음)`)) {
+      return
+    }
+    try {
+      const params = {}
+      if (date) {
+        params.from_ts = dayStart(date)
+        params.to_ts = dayEnd(date)
+      }
+      const res = await api.clearLogs(params)
+      setMsg(`${res.deleted.toLocaleString()}건 삭제됨`)
+      setError(null)
+      setTimeout(() => setMsg(null), 2500)
+      load()
+    } catch (e) {
+      setError(e.message)
+    }
+  }
+
+  const clearLabel = date ? `${date} 하루치 삭제` : '전체 로그 초기화'
 
   return (
     <div>
@@ -40,6 +80,19 @@ export default function Logs() {
           <option value="blocked">차단</option>
           <option value="error">에러</option>
         </select>
+        <label className="inline">
+          날짜
+          <input
+            type="date"
+            value={date}
+            onChange={(e) => setDate(e.target.value)}
+          />
+        </label>
+        {date && (
+          <button className="ghost" onClick={() => setDate('')}>
+            오늘 해제
+          </button>
+        )}
         <label className="inline">
           <input
             type="checkbox"
@@ -49,6 +102,10 @@ export default function Logs() {
           자동 갱신 (3초)
         </label>
         <span className="muted">총 {data.total.toLocaleString()}건</span>
+        <button className="danger" onClick={clearLogs}>
+          {clearLabel}
+        </button>
+        {msg && <span className="ok">{msg}</span>}
       </div>
       <table className="table">
         <thead>