all: delete the code nothing calls

From the audit (#5178). Each was unreachable from every client:

- Checklist add-item and delete-item: REST POST /items and DELETE /items/<id>,
  the Tauri commands, the store, rest and local adapters, the core's
  add_item/delete_item, set_item_text and remove_item, and the FFI exports.
  Adding, rewording and removing an item are body edits in every editor. The
  checked toggle stays, and its rewriter is simpler without the drop branch.
- Manual unfurl: POST /unfurl and its adapters. Previews arrive in the
  background after a save (unfurl_queue).
- The /api/config `android_client` key, android_release() and the
  APK_NAME/MANIFEST_NAME aliases. Phones poll /api/client/android.
- users.email_verified and users.avatar_path (migration 0037). Nothing set
  the first or read the second; the SMTP reset never checked verification.
- derive::extract_tags (only tests used it; the shared fixture now runs
  through extract_tag_spans), the unused check and link icons, and the
  unused editor_add_item string.
- The blob scheme is renamed tsblob -> inkblob. URLs are built as notes are
  read, so nothing stored carries the old one.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

core/src/local/store.rs

@@ -756,14 +756,13 @@ pub fn set_labels(conn: &Connection, id: &str, label_ids: &[String]) -> rusqlite
     load_note(conn, id)
 }
 
-// ---- checklist items: every one of these is a body edit ---------------------
+// ---- checklist items: a tick is a body edit ----------------------------------
 //
-// They keep their own names and signatures because the FFI, the Tauri commands and
-// the REST shape all speak in items, and a checklist is still a thing a note HAS.
-// What changed is where it is kept. Routing all three through `update_note` rather
-// than writing the body directly is what gives them revision snapshotting, `#tag`
-// re-derivation and the dirty/updated_at bookkeeping without any of it being
-// written a second time here.
+// It keeps the item's name and signature because the FFI, the Tauri commands and the
+// REST shape all speak in items, and a checklist is still a thing a note HAS. Routing
+// it through `update_note` rather than writing the body directly is what gives it
+// revision snapshotting, `#tag` re-derivation and the dirty/updated_at bookkeeping
+// without any of it being written a second time here.
 
 fn note_body(conn: &Connection, id: &str) -> rusqlite::Result<String> {
     conn.query_row("SELECT body FROM notes WHERE id = ?1", [id], |r| r.get(0))
@@ -779,11 +778,8 @@ fn set_body(conn: &Connection, id: &str, body: String) -> rusqlite::Result<Note>
     update_note(conn, id, &json!({ "body": body }))
 }
 
-pub fn add_item(conn: &Connection, id: &str, text: &str) -> rusqlite::Result<Note> {
-    let body = note_body(conn, id)?;
-    set_body(conn, id, derive::append_item(&body, text, false))
-}
-
+/// Tick or untick one item. The only item change that isn't an edit to the body's
+/// text: adding, rewording and removing an item happen in the editor.
 pub fn update_item(
     conn: &Connection,
     id: &str,
@@ -795,24 +791,12 @@ pub fn update_item(
         None => return load_note(conn, id),
     };
     let mut body = note_body(conn, id)?;
-    if let Some(text) = changes.get("text").and_then(Value::as_str) {
-        body = derive::set_item_text(&body, index, text);
-    }
     if let Some(checked) = changes.get("checked").and_then(Value::as_bool) {
         body = derive::set_item_checked(&body, index, checked);
     }
     set_body(conn, id, body)
 }
 
-pub fn delete_item(conn: &Connection, id: &str, item_id: &str) -> rusqlite::Result<Note> {
-    let index = match item_index(item_id) {
-        Some(i) => i,
-        None => return load_note(conn, id),
-    };
-    let body = note_body(conn, id)?;
-    set_body(conn, id, derive::remove_item(&body, index))
-}
-
 /// The stored form of a declared content type: the bare media type, lowercase.
 /// Matches the server's `normalize_mime`, so both sides file a type the same way.
 fn normalize_mime(raw: &str) -> String {
@@ -1355,7 +1339,7 @@ mod tests {
             .expect("refused");
         // The words the person sees, exactly: the refusal prints as its message.
         assert_eq!(refused.to_string(), VIEW_ONLY);
-        assert!(add_item(&conn, "n", "eggs").is_err());
+        assert!(update_item(&conn, "n", "0", &json!({ "checked": true })).is_err());
         assert!(trash(&conn, "n").is_err());
         assert!(snooze_reminder(&conn, "n", 10).is_err());
         assert!(set_labels(&conn, "n", &[]).is_err());
@@ -1374,7 +1358,7 @@ mod tests {
         assert!(edited.labels.is_empty());
         assert_eq!(edited.body, "their words, edited\n#mine");
         assert!(dirty(&conn, "n"));
-        add_item(&conn, "n", "eggs").expect("an item is text");
+        update_item(&conn, "n", "0", &json!({ "checked": true })).expect("a tick is text");
 
         let reminded = update_note(
             &conn,