Add a Card Search tab and fix horizontal-card (Battle/Plane) preview orientation

Card Search browses the whole downloaded card universe (not just owned
cards), reusing the Library tab's filter/group/sort/list/tiles UI; results
show ownership and offer quick "own" and "add to deck" actions.

Battles, Planes, and Phenomena store their Scryfall image portrait-shaped
with the content itself rotated, so hover/click previews now detect this
(a new `horizontal` flag threaded through ingest and every card query, with
graceful fallback for a reference.db built before the column existed) and
rotate the image back into place. Single-faced and non-DFC cases are
verified fixed; a double-faced Battle's front face still needs another pass.

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>

crates/mtgc-core/src/model.rs

@@ -152,6 +152,11 @@ pub struct CardRef {
     pub colors: ColorSet,
     pub color_identity: ColorSet,
     pub type_line: String,
+    /// Whether this card is printed/displayed sideways (Scryfall layout
+    /// "battle" or "planar" — Battles, Planes, and Phenomena). Its stored
+    /// image is itself portrait-shaped with the content rotated, so viewers
+    /// must rotate it 90° to display right-side up.
+    pub horizontal: bool,
     /// URL of a card image (Scryfall "normal" size) for one of its printings,
     /// or empty if none is available.
     pub image_uri: String,