Add HttpInfluxClient for HTTPS/Cloudflare environments; v0.2.1

gRPC/Arrow Flight is blocked through Cloudflare tunnels (HTTP/2 not
passed through). HttpInfluxClient uses /api/v3/query_sql over plain
HTTPS with JSON responses as a drop-in replacement for InfluxDBClient3.

Auto-selected by get_influx_client() when host starts with https://.
Local http:// stacks continue to use InfluxDBClient3 (gRPC).

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

Author: haoruizhou

src/slicks/fetcher.py

@@ -16,6 +16,7 @@ def __init__(self, v):
         self._v = v
 
     def as_py(self):
+        """Return the wrapped Python value."""
         return self._v
 
 
@@ -33,9 +34,11 @@ def __init__(self, df: pd.DataFrame):
 
     @property
     def num_rows(self) -> int:
+        """Number of rows in the result."""
         return len(self._df)
 
     def column(self, name: str) -> List[_Scalar]:
+        """Return a column as a list of _Scalar values with .as_py()."""
         if name not in self._df.columns:
             return []
         return [_Scalar(v) for v in self._df[name]]
@@ -85,12 +88,15 @@ def query(self, query: str, mode: str = None, database: str = None, **kwargs) ->
         return _ArrowLike(df)
 
     def close(self):
+        """No-op — kept for interface compatibility with InfluxDBClient3."""
         pass
 
     def __enter__(self):
+        """Context manager entry."""
         return self
 
     def __exit__(self, *_):
+        """Context manager exit."""
         pass