feat: remove spine-set-status, update edit functions for level-2 headlines

spine.el

@@ -302,30 +302,6 @@ Keyword arguments: :title :author :shelf :format :isbn :cover
               t)
           (kill-buffer))))))
 
-(defun spine-set-status (id status)
-  "Set the TODO state of book with ID to STATUS.
-STATUS should be one of: WANT, READING, READ, ABANDONED.
-Signals an error if the book is not found."
-  (let ((org-file (expand-file-name spine-org-file)))
-    (unless (file-exists-p org-file)
-      (error "spine-set-status: file not found: %s" org-file))
-    (with-current-buffer (find-file-noselect org-file)
-      (unwind-protect
-          (progn
-            (org-element-map (org-element-parse-buffer 'headline) 'headline
-              (lambda (hl)
-                (when (= (org-element-property :level hl) 1)
-                  (let ((pos (org-element-property :begin hl)))
-                    (when (equal id (spine--prop pos "ID"))
-                      (goto-char pos)
-                      (org-todo status)))))
-              nil 'headline)
-            (unless (eq (point) (point-min))
-              (save-buffer)
-              t)
-            (when (eq (point) (point-min))
-              (error "spine-set-status: no book found with ID %s" id)))
-        (kill-buffer)))))
 
 (defun spine-add-note (id text &optional date)
   "Append a reading note to the book with ID.
@@ -340,7 +316,7 @@ TEXT is the note content. DATE is an optional YYYY-MM-DD string
           (progn
             (org-element-map (org-element-parse-buffer 'headline) 'headline
               (lambda (hl)
-                (when (= (org-element-property :level hl) 1)
+                (when (= (org-element-property :level hl) 2)
                   (let ((hl-id (spine--prop (org-element-property :begin hl) "ID")))
                     (when (equal id hl-id)
                       (goto-char (org-element-property :end hl))
@@ -365,7 +341,7 @@ Signals an error if the book is not found."
           (progn
             (org-element-map (org-element-parse-buffer 'headline) 'headline
               (lambda (hl)
-                (when (= (org-element-property :level hl) 1)
+                (when (= (org-element-property :level hl) 2)
                   (let ((pos (org-element-property :begin hl)))
                     (when (equal id (spine--prop pos "ID"))
                       (goto-char pos)