feat: add DockingEvent model and docking styles

- Add DockingEvent model with parent/child asset relations, docked_at/undocked_at timestamps
- Add docking migration for new docking_events table
- Add .ad-dock, .ad-dock-box, .ad-dock-item, .ad-undock CSS classes

Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>

app/models.py

@@ -145,6 +145,44 @@ class Asset(TimestampMixin, db.Model):
         lazy="selectin",
         order_by="AssetLogEntry.start_at",
     )
+    docking_children: Mapped[list["DockingEvent"]] = relationship(
+        back_populates="parent_asset",
+        cascade="all, delete-orphan",
+        foreign_keys="DockingEvent.parent_asset_id",
+        lazy="selectin",
+    )
+    docking_parents: Mapped[list["DockingEvent"]] = relationship(
+        back_populates="child_asset",
+        cascade="all, delete-orphan",
+        foreign_keys="DockingEvent.child_asset_id",
+        lazy="selectin",
+    )
+
+
+class DockingEvent(TimestampMixin, db.Model):
+    __tablename__ = "docking_events"
+
+    id: Mapped[uuid.UUID] = mapped_column(Uuid, primary_key=True, default=uuid.uuid4)
+    parent_asset_id: Mapped[uuid.UUID] = mapped_column(
+        Uuid, ForeignKey("assets.id", ondelete="CASCADE"), nullable=False, index=True
+    )
+    child_asset_id: Mapped[uuid.UUID | None] = mapped_column(
+        Uuid, ForeignKey("assets.id", ondelete="SET NULL"), nullable=True, index=True
+    )
+    child_label: Mapped[str | None] = mapped_column(String(255))
+    docked_at: Mapped[datetime] = mapped_column(DateTime(timezone=True), nullable=False, index=True)
+    undocked_at: Mapped[datetime | None] = mapped_column(DateTime(timezone=True), index=True)
+    dock_note: Mapped[str | None] = mapped_column(Text)
+    undock_note: Mapped[str | None] = mapped_column(Text)
+
+    parent_asset: Mapped[Asset] = relationship(
+        back_populates="docking_children",
+        foreign_keys=[parent_asset_id],
+    )
+    child_asset: Mapped[Asset | None] = relationship(
+        back_populates="docking_parents",
+        foreign_keys=[child_asset_id],
+    )
 
 
 class AssetLogEntry(TimestampMixin, db.Model):
@@ -156,9 +194,7 @@ class AssetLogEntry(TimestampMixin, db.Model):
     )
     entry_kind: Mapped[str] = mapped_column(String(16), nullable=False)
     title: Mapped[str] = mapped_column(String(255), nullable=False)
-    state_label: Mapped[str | None] = mapped_column(String(120))
     mission_label: Mapped[str | None] = mapped_column(String(255))
-    location: Mapped[str | None] = mapped_column(String(255))
     start_at: Mapped[datetime] = mapped_column(DateTime(timezone=True), nullable=False, index=True)
     end_at: Mapped[datetime | None] = mapped_column(DateTime(timezone=True))
     summary: Mapped[str | None] = mapped_column(Text)
@@ -183,5 +219,9 @@ class AssetStateNode(TimestampMixin, db.Model):
     title: Mapped[str] = mapped_column(String(255), nullable=False)
     detail: Mapped[str | None] = mapped_column(Text)
     at_time: Mapped[datetime] = mapped_column(DateTime(timezone=True), nullable=False, index=True)
+    target_location: Mapped[str | None] = mapped_column(String(255))
+    previous_location: Mapped[str | None] = mapped_column(String(255))
+    transit_location: Mapped[str | None] = mapped_column(String(255))
+    state_label: Mapped[str | None] = mapped_column(String(120))
 
     entry: Mapped[AssetLogEntry] = relationship(back_populates="state_nodes")