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".

api/routes/logs.py

@@ -1,4 +1,4 @@
-"""접속 로그 조회."""
+"""접속 로그 조회 및 초기화."""
 from __future__ import annotations
 
 import sqlite3
@@ -15,16 +15,26 @@ def list_logs(
     limit: int = Query(50, ge=1, le=500),
     offset: int = Query(0, ge=0),
     action: str | None = Query(None),
+    from_ts: float | None = Query(None, description="unix epoch seconds, inclusive"),
+    to_ts: float | None = Query(None, description="unix epoch seconds, exclusive"),
 ) -> dict:
     if not LOG_DB.exists():
         return {"total": 0, "items": []}
     con = sqlite3.connect(LOG_DB)
     try:
         con.row_factory = sqlite3.Row
-        where, params = "", []
+        conds: list[str] = []
+        params: list = []
         if action:
-            where = "WHERE action = ?"
+            conds.append("action = ?")
             params.append(action)
+        if from_ts is not None:
+            conds.append("ts >= ?")
+            params.append(from_ts)
+        if to_ts is not None:
+            conds.append("ts < ?")
+            params.append(to_ts)
+        where = ("WHERE " + " AND ".join(conds)) if conds else ""
         total = con.execute(
             f"SELECT COUNT(*) FROM connections {where}", params
         ).fetchone()[0]
@@ -36,3 +46,40 @@ def list_logs(
     finally:
         con.close()
     return {"total": total, "items": [dict(r) for r in rows]}
+
+
+@router.delete("/logs")
+def clear_logs(
+    from_ts: float | None = Query(None, description="ts >= from_ts 만 삭제"),
+    to_ts: float | None = Query(None, description="ts < to_ts 만 삭제"),
+) -> dict:
+    """접속 로그를 삭제한다.
+
+    - from_ts/to_ts 둘 다 없으면 전체 삭제 (AUTOINCREMENT 카운터까지 리셋)
+    - 둘 중 하나만 있으면 그 조건만 적용
+    - 둘 다 있으면 [from_ts, to_ts) 범위 삭제 — 날짜 선택 삭제 용도
+    """
+    if not LOG_DB.exists():
+        return {"deleted": 0}
+    con = sqlite3.connect(LOG_DB, timeout=5)
+    try:
+        conds: list[str] = []
+        params: list = []
+        if from_ts is not None:
+            conds.append("ts >= ?")
+            params.append(from_ts)
+        if to_ts is not None:
+            conds.append("ts < ?")
+            params.append(to_ts)
+        if conds:
+            where = "WHERE " + " AND ".join(conds)
+            cur = con.execute(f"DELETE FROM connections {where}", params)
+            deleted = cur.rowcount
+        else:
+            cur = con.execute("DELETE FROM connections")
+            deleted = cur.rowcount
+            con.execute("DELETE FROM sqlite_sequence WHERE name='connections'")
+        con.commit()
+    finally:
+        con.close()
+    return {"deleted": deleted}