fix(tdd): replace non-standard @tdd_bug tags with @tdd_issue per CONTRIBUTING.md

Reviewed and APPROVED. Closes #2779.

features/tdd_actor_list_no_db_update.feature

@@ -1,4 +1,4 @@
-@tdd_bug @tdd_bug_797
+@tdd_issue @tdd_issue_797
 Feature: TDD Bug #797 — actor list should not cause a database update
 
   Bug #797 reports that running ``agents actor list`` on a fresh checkout

features/tdd_exec_env_resolution_precedence.feature

@@ -1,4 +1,4 @@
-@tdd_issue @tdd_issue_1080 @tdd_bug @tdd_bug_1080 @mock_only
+@tdd_issue @tdd_issue_1080 @mock_only
 Feature: TDD Bug #1080 — execution environment resolution ignores project-level override
   As a developer
   I want execution environment resolution to honour the 6-level precedence chain

features/tdd_use_action_automation_profile.feature

@@ -1,4 +1,4 @@
-@tdd_bug @tdd_bug_1076
+@tdd_issue @tdd_issue_1076
 Feature: TDD Bug #1076 — use_action() does not propagate automation_profile to Plan
   As a developer
   I want to verify that use_action() resolves the automation profile