chore(1001): retire recover_half_written_items from MCP surface

The recovery tool was a one-shot migration aid for the half-written
items that existed before the Stage 1 allocator fix. The three live
orphans (989/1000/1001) have been migrated; the Stage 1 fix prevents
new half-writes; the tool's job is done.

Removes the MCP wrapper, schema, dispatch case, and tools-list
assertion. The db::recover module itself stays in-process (under
`#[allow(dead_code)]`) so it can be re-exposed quickly if the bug
ever resurfaces — its regression tests still run as part of the
default suite.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

server/src/http/mcp/tools_list/mod.rs

@@ -96,7 +96,6 @@ mod tests {
         assert!(names.contains(&"status"));
         assert!(names.contains(&"loc_file"));
         assert!(names.contains(&"dump_crdt"));
-        assert!(names.contains(&"recover_half_written_items"));
         assert!(names.contains(&"get_version"));
         assert!(names.contains(&"remove_criterion"));
         assert!(names.contains(&"mesh_status"));
@@ -107,7 +106,7 @@ mod tests {
         assert!(names.contains(&"show_epic"));
         assert!(names.contains(&"freeze_story"));
         assert!(names.contains(&"unfreeze_story"));
-        assert_eq!(tools.len(), 75);
+        assert_eq!(tools.len(), 74);
     }
 
     #[test]