US06-01: Configure and Preflight Archive Destinations (#77)

photo_pipeline/models/__init__.py

@@ -5,6 +5,7 @@ Alembic environment relies on.
 """
 
 from photo_pipeline.models.albums import AlbumProposal
+from photo_pipeline.models.archives import ArchiveLocation
 from photo_pipeline.models.assets import Asset, AssetPath
 from photo_pipeline.models.duplicates import (
     DuplicateCluster,
@@ -19,6 +20,7 @@ from photo_pipeline.models.workflow import AnalysisResult, SafetyReview
 
 __all__ = [
     "AlbumProposal",
+    "ArchiveLocation",
     "Asset",
     "AssetPath",
     "DuplicateCluster",

photo_pipeline/models/archives.py

@@ -0,0 +1,42 @@
+"""Archive location persistence (US06-01).
+
+An archive location is a *medium*, not a path. External disks get mounted at
+different mountpoints, and a different disk can be mounted at the same one, so a
+recorded root alone can never prove "these bytes went to that volume". Each
+location therefore owns a marker file written onto the medium itself; its
+``media_id`` is the stable identity, and the root is only where it was last seen.
+
+``capabilities`` and ``state`` are the last probe result, kept so the UI can list
+locations without touching a sleeping disk. Preflight always re-probes — a stored
+state is a hint, never evidence.
+"""
+
+from __future__ import annotations
+
+from datetime import datetime
+
+from sqlalchemy import DateTime, String, func
+from sqlalchemy.orm import Mapped, mapped_column
+
+from photo_pipeline.db import Base
+
+
+class ArchiveLocation(Base):
+    __tablename__ = "archive_locations"
+
+    id: Mapped[str] = mapped_column(String, primary_key=True)
+    name: Mapped[str] = mapped_column(String, nullable=False, unique=True)
+    root: Mapped[str] = mapped_column(String, nullable=False)
+    # Written into the marker file on the medium; proves the right volume is mounted.
+    media_id: Mapped[str] = mapped_column(String, nullable=False, unique=True)
+    capabilities: Mapped[str | None] = mapped_column(String)  # JSON, last probe
+    # online | offline | wrong_volume | unwritable — the last probe's verdict.
+    state: Mapped[str] = mapped_column(String, nullable=False, default="offline")
+    last_seen_at: Mapped[datetime | None] = mapped_column(DateTime(timezone=True))
+
+    created_at: Mapped[datetime] = mapped_column(
+        DateTime(timezone=True), nullable=False, server_default=func.now()
+    )
+    updated_at: Mapped[datetime] = mapped_column(
+        DateTime(timezone=True), nullable=False, server_default=func.now(), onupdate=func.now()
+    )