feat(git): blob entries from a tree get filetype-aware loading

lua/git/object.lua

@@ -261,17 +261,33 @@ function M.open_under_cursor()
 
     -- Cat-file header navigation: `parent <sha>` (commit), `tree <sha>`
     -- (commit / tag), `object <sha>` (tag's referent) all reference
-    -- another git object. Tree-entry lines `<mode> <type> <sha>\t<name>`
-    -- navigate to a child blob or subtree.
+    -- another git object.
     local sha = line:match("^parent (%x+)$")
         or line:match("^tree (%x+)$")
         or line:match("^object (%x+)$")
-        or line:match("^%d+ %w+ (%x+)\t.+$")
     if sha then
         M.open_object(ctx.worktree, sha, { split = false })
         return true
     end
 
+    -- Tree-entry navigation: `<mode> <type> <sha>\t<name>`. Blob entries
+    -- route through `diff.git_show_buf` so the buffer URI carries the
+    -- entry name and BufReadCmd / BufReadPost resolve filetype from it.
+    -- Other types (subtrees, submodule commit refs, tags) fall through
+    -- to the generic SHA-based opener.
+    local entry_type, entry_sha, entry_name =
+        line:match("^%d+ (%w+) (%x+)\t(.+)$")
+    if entry_sha then
+        if entry_type == "blob" then
+            local buf = diff.git_show_buf(ctx.worktree, ctx.ref, entry_name)
+            vim.cmd.normal({ "m'", bang = true })
+            vim.api.nvim_set_current_buf(buf)
+        else
+            M.open_object(ctx.worktree, entry_sha, { split = false })
+        end
+        return true
+    end
+
     local section = diff_section()
     if not section then
         return false