refactor(probe): consolidate full probe() into MediaProber port

Add probe(video) -> MediaInfo | None to the MediaProber Protocol and
implement it on FfprobeMediaProber. The standalone
alfred/infrastructure/filesystem/ffprobe.py module is removed; all
callers (analyze_release / probe_media tools, testing scripts) now go
through the adapter.

Tests for the probe path moved to tests/infrastructure/test_ffprobe_prober.py
(patching subprocess.run at the adapter module level).

Unblocks the upcoming inspect_release orchestrator, which needs the
port — not a free function — to compose parse + main-video selection
+ probe in one shot.

alfred/domain/shared/ports/media_prober.py

@@ -9,7 +9,10 @@ from __future__ import annotations
 
 from dataclasses import dataclass
 from pathlib import Path
-from typing import Protocol
+from typing import TYPE_CHECKING, Protocol
+
+if TYPE_CHECKING:
+    from alfred.domain.shared.media import MediaInfo
 
 
 @dataclass(frozen=True)
@@ -37,3 +40,13 @@ class MediaProber(Protocol):
         no subtitle streams. Adapters must not raise.
         """
         ...
+
+    def probe(self, video: Path) -> MediaInfo | None:
+        """Return the full :class:`MediaInfo` for ``video``, or ``None``.
+
+        Covers all stream families (video, audio, subtitle) plus
+        file-level duration / bitrate. ``None`` signals that ffprobe is
+        unavailable or the file can't be read — adapters must not
+        raise.
+        """
+        ...