feat(core): ALIAS_SUFFIX + strip_alias_suffix (dense alias vectors)

crates/kebab-core/src/ids.rs

@@ -58,6 +58,15 @@ fn validate_hex32(s: &str) -> Result<(), CoreError> {
     Ok(())
 }
 
+/// Suffix appended to a chunk's vector ID to mark an alias embedding row.
+pub const ALIAS_SUFFIX: &str = "#alias";
+
+/// Strip `#alias` suffix from `id`, returning the bare chunk ID.
+/// If `id` does not end with `ALIAS_SUFFIX`, returns `id` unchanged.
+pub fn strip_alias_suffix(id: &str) -> &str {
+    id.strip_suffix(ALIAS_SUFFIX).unwrap_or(id)
+}
+
 /// Canonical-JSON + blake3 + hex prefix 32. Per design §4.2.
 pub fn id_from<T: Serialize>(tuple: T) -> String {
     let bytes = serde_json_canonicalizer::to_vec(&tuple)
@@ -430,6 +439,16 @@ mod tests {
         assert_eq!(id.0, "71992c457a5da39880a6d17d646ed0fd");
     }
 
+    #[test]
+    fn strip_alias_suffix_roundtrip() {
+        let bare = "0123456789abcdef0123456789abcdef";
+        let with_suffix = format!("{}{}", bare, ALIAS_SUFFIX);
+        assert_eq!(strip_alias_suffix(&with_suffix), bare);
+        assert_eq!(strip_alias_suffix(bare), bare);
+        assert_eq!(strip_alias_suffix(""), "");
+        assert_eq!(strip_alias_suffix("#alias"), "");
+    }
+
     /// Independent pin for id_for_index.
     /// inputs:
     ///   collection="default",

crates/kebab-core/src/lib.rs

@@ -43,8 +43,9 @@ pub use document::{
 pub use errors::CoreError;
 pub use fetch::{FetchKind, FetchOpts, FetchQuery, FetchResult};
 pub use ids::{
-    AssetId, BlockId, ChunkId, DocumentId, EmbeddingId, IndexId, id_for_asset, id_for_block,
-    id_for_chunk, id_for_doc, id_for_embedding, id_for_index, id_from,
+    ALIAS_SUFFIX, AssetId, BlockId, ChunkId, DocumentId, EmbeddingId, IndexId, id_for_asset,
+    id_for_block, id_for_chunk, id_for_doc, id_for_embedding, id_for_index, id_from,
+    strip_alias_suffix,
 };
 pub use ingest::{IngestItem, IngestItemKind, IngestReport, SkipExamples};
 pub use jobs::{JobFilter, JobId, JobKind, JobRow, JobStatus};