feat(git): route :G cat-file -p <sha> through the object viewer

lua/git/cmd.lua

@@ -98,6 +98,17 @@ local function run_in_split(worktree, args, conf)
         end
     end
 
+    -- `cat-file -p <sha>` routes to the gitobject viewer so commits get
+    -- the full message + diff view and other types render via cat-file.
+    -- Other modes (-t, -s, -e) fall through to the generic dump.
+    if args[1] == "cat-file" and vim.list_contains(args, "-p") then
+        local ref = first_positional(args, 2)
+        if ref then
+            require("git.object").open_object(worktree, ref)
+            return
+        end
+    end
+
     local buf = git.new_scratch()
     vim.b[buf].git_worktree = worktree
     if conf.needs_ref then