refactor: clean up pull request comment related code and template dict (#39789)

1. drop comment.commit_id
2. refactor templates, remove `dict "." .` from templates

modelmigration/migrations.go

@@ -437,6 +437,7 @@ func prepareMigrationTasks() []*migration {
 		newMigration(358, "Track previous remember-me token hashes", v29.AddPreviousAuthTokenHash),
 		newMigration(359, "Add stage and number columns to action_task_step", v29.AddStageAndNumberToActionTaskStep),
 		newMigration(360, "Move branch protection settings to JSON", v29.MoveBranchProtectionConfigToJSON),
+		newMigration(361, "Drop legacy commit_id column from comment", v29.DropCommentCommitID),
 	}
 	return preparedMigrations
 }

modelmigration/v29/v361.go

@@ -0,0 +1,21 @@
+// Copyright 2026 The Gitea Authors. All rights reserved.
+// SPDX-License-Identifier: MIT
+
+package v29
+
+import (
+	"context"
+
+	"gitea.dev/modelmigration/base"
+)
+
+func DropCommentCommitID(ctx context.Context, x base.EngineMigration) error {
+	exists, err := x.Dialect().IsColumnExist(x.DB(), ctx, "comment", "commit_id")
+	if err != nil || !exists {
+		return err
+	}
+
+	return base.EngineTransaction(x, func(sess base.Session) error {
+		return base.DropTableColumns(sess, "comment", "commit_id")
+	})
+}