Initial commit: DeltaGlider - S3-compatible storage with 99.9% compression

- Drop-in replacement for AWS S3 CLI (cp, ls, rm, sync commands)
- Binary delta compression using xdelta3
- Hexagonal architecture with clean separation of concerns
- Achieves 99.9% compression for versioned files
- Full test suite with 100% passing tests
- Python 3.11+ support

src/deltaglider/adapters/diff_xdelta.py

@@ -20,7 +20,8 @@ class XdeltaAdapter(DiffPort):
             "-e",  # encode
             "-f",  # force overwrite
             "-9",  # compression level
-            "-s", str(base),  # source file
+            "-s",
+            str(base),  # source file
             str(target),  # target file
             str(out),  # output delta
         ]
@@ -40,7 +41,8 @@ class XdeltaAdapter(DiffPort):
             self.xdelta_path,
             "-d",  # decode
             "-f",  # force overwrite
-            "-s", str(base),  # source file
+            "-s",
+            str(base),  # source file
             str(delta),  # delta file
             str(out),  # output file
         ]

src/deltaglider/adapters/logger_std.py

@@ -18,9 +18,7 @@ class StdLoggerAdapter(LoggerPort):
 
         if not self.logger.handlers:
             handler = logging.StreamHandler(sys.stderr)
-            formatter = logging.Formatter(
-                "%(asctime)s - %(name)s - %(levelname)s - %(message)s"
-            )
+            formatter = logging.Formatter("%(asctime)s - %(name)s - %(levelname)s - %(message)s")
             handler.setFormatter(formatter)
             self.logger.addHandler(handler)
 

src/deltaglider/adapters/metrics_noop.py

@@ -1,6 +1,5 @@
 """No-op metrics adapter."""
 
-
 from ..ports.metrics import MetricsPort
 
 

src/deltaglider/adapters/storage_s3.py

@@ -51,7 +51,12 @@ class S3StorageAdapter(StoragePort):
 
     def list(self, prefix: str) -> Iterator[ObjectHead]:
         """List objects by prefix."""
-        bucket, prefix_key = self._parse_key(prefix)
+        # Handle bucket-only prefix (e.g., "bucket" or "bucket/")
+        if "/" not in prefix:
+            bucket = prefix
+            prefix_key = ""
+        else:
+            bucket, prefix_key = self._parse_key(prefix)
 
         paginator = self.client.get_paginator("list_objects_v2")
         pages = paginator.paginate(Bucket=bucket, Prefix=prefix_key)
@@ -69,7 +74,7 @@ class S3StorageAdapter(StoragePort):
 
         try:
             response = self.client.get_object(Bucket=bucket, Key=object_key)
-            return response["Body"]
+            return response["Body"]  # type: ignore[return-value]
         except ClientError as e:
             if e.response["Error"]["Code"] == "NoSuchKey":
                 raise FileNotFoundError(f"Object not found: {key}") from e
@@ -133,4 +138,3 @@ class S3StorageAdapter(StoragePort):
         """Extract user metadata from S3 response."""
         # S3 returns user metadata as-is (already lowercase)
         return raw_metadata
-