android: search narrows the board in view, and combines with its filters

As on the web, the search box is now one more facet on the board you are
looking at, rather than a separate unfiltered search. "These words, in
notes tagged grocery" works: on the main board the text is sent to the
core together with the Filters sheet's tags, attachment and shared
switches, and the core ANDs them in list_notes. Archive, Trash and a
tag's view take the text alone. A search typed on Reminders, which is not
a board view, moves to the main board, as the web does.

The Filters chip stays while you search; it was hidden before, on the
mistaken claim that the web hides its filters too. Drag-to-reorder stays
off during a search, since a filtered subset can't be renumbered against
notes it can't see.

store::search and the FFI's search_notes had no other callers, and are
removed. They also searched archived notes and ignored pinning, which the
board's query does not.

Scribe #2942.

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

android/ffi/src/lib.rs

@@ -171,17 +171,6 @@ impl Inkwell {
             .map_err(CoreError::store)
     }
 
-    /// Full-text search across titles, bodies and checklist items.
-    ///
-    /// The core owns the query — it searches the same columns the desktop and web
-    /// search, so "what matches" cannot drift between surfaces. Filtering the
-    /// board list in Kotlin would have been less code and a different product.
-    pub fn search_notes(&self, query: String) -> Result<Vec<Note>, CoreError> {
-        let conn = self.db.conn().map_err(CoreError::store)?;
-        let notes = local::store::search(&conn, &query).map_err(CoreError::store)?;
-        Ok(notes.into_iter().map(Note::from).collect())
-    }
-
     /// Notes carrying a reminder, soonest first.
     ///
     /// A dedicated call rather than a board `view`, because that is how the core