Keep the dense landmarks behind each eye reading, packed

The 106 points the eye boxes were cut from, stored beside the reading as
16-bit fixed point over the frame: 424 bytes a face, a seventh of a pixel
on a 6000-pixel frame, where f16 at the same size would have been six.
Derived data like the embedding, kept for the same reason — it cost a
fetch and a model run, and the next per-face pass should run from the
catalog. Shards carry it; a peer's shard from before it is still read.

core/dr-catalog/src/schema.rs

@@ -15,7 +15,7 @@ use rusqlite::Connection;
 use crate::error::CatalogError;
 
 /// Schema version this build writes and understands.
-pub const SCHEMA_VERSION: i64 = 17;
+pub const SCHEMA_VERSION: i64 = 18;
 
 /// Apply migrations up to [`SCHEMA_VERSION`].
 ///
@@ -167,6 +167,20 @@ pub fn migrate(conn: &Connection) -> Result<i64, CatalogError> {
         tx.commit()?;
     }
 
+    if from < 18 {
+        let tx = conn.unchecked_transaction()?;
+        // Guarded like V14's and V16's columns: ALTER has no IF NOT EXISTS
+        // and the step must be re-enterable (NFR-R5).
+        let present: bool = tx
+            .prepare("SELECT 1 FROM pragma_table_info('faces') WHERE name = 'landmarks_dense'")?
+            .exists([])?;
+        if !present {
+            tx.execute_batch("ALTER TABLE faces ADD COLUMN landmarks_dense BLOB;")?;
+        }
+        tx.pragma_update(None, "user_version", 18)?;
+        tx.commit()?;
+    }
+
     Ok(from)
 }
 
@@ -348,7 +362,8 @@ pub fn for_attached(schema_name: &str) -> String {
          ALTER TABLE {schema_name}.faces ADD COLUMN eye_left REAL;\n\
          ALTER TABLE {schema_name}.faces ADD COLUMN eye_left_px REAL;\n\
          ALTER TABLE {schema_name}.faces ADD COLUMN eye_left_sharp REAL;\n\
-         ALTER TABLE {schema_name}.faces ADD COLUMN sunglasses REAL;",
+         ALTER TABLE {schema_name}.faces ADD COLUMN sunglasses REAL;\n\
+         ALTER TABLE {schema_name}.faces ADD COLUMN landmarks_dense BLOB;",
         rewrite_for_attached(V1, schema_name),
         rewrite_for_attached(V6, schema_name),
         rewrite_for_attached(V8, schema_name),
@@ -751,6 +766,19 @@ CREATE TABLE IF NOT EXISTS xmp_conflicts (
 );
 "#;
 
+// V18 -- TRACES: FR-CULL-8a | FR-CULL-12
+//
+// The 106 dense landmarks the eye pass reads its eye boxes from, kept beside
+// the reading as `dr_face::Landmarks::to_packed_bytes`: 106 x (x, y) as
+// 16-bit fixed point over the frame, 424 bytes a face, a seventh of a
+// pixel on a 6000-pixel frame. Derived data under FR-CULL-12 -- rebuilt by
+// re-reading, never in a sidecar -- and stored for the same reason the
+// embedding is: it cost a fetch of the original and a model run, and the
+// next per-face pass (head pose, expression) should not have to pay either
+// again. NULL where the face was never read.
+//
+// Added in `migrate`, guarded, like every ALTER here (NFR-R5).
+
 const V17: &str = r#"
 -- TRACES: FR-CULL-8a | FR-CULL-13 | NFR-P9
 -- The eyes-open filter's index, and a lesson about where a column lands.