refactor(phase-6): remove scale testing plan, simplify to docker + runbook

- Delete PLAN-02-SCALE-TESTING.md (scale testing deferred to v3)
- Rename PLAN-03-BACKUP-RUNBOOK to PLAN-02-OPERATIONAL-RUNBOOK
- Phase 6 now has 2 executable plans instead of 3

.claude/settings.local.json

@@ -100,7 +100,18 @@
       "Skill(gsd-resume-work)",
       "Bash(git revert *)",
       "Skill(gsd-next)",
-      "Bash(grep -E \"\\\\.\\(tsx|ts\\)$\")"
+      "Bash(grep -E \"\\\\.\\(tsx|ts\\)$\")",
+      "Skill(gsd-new-project)",
+      "mcp__plugin_context-mode_context-mode__ctx_fetch_and_index",
+      "Skill(gsd-insert-phase)",
+      "Bash(gsd-sdk query *)",
+      "Skill(gsd-plan-phase)",
+      "Skill(gsd-execute-phase)",
+      "Skill(gsd-verify-work)",
+      "Skill(gsd-discuss-phase)",
+      "Skill(gsd-code-review)",
+      "Skill(gsd-progress)",
+      "Skill(gsd-code-review-fix)"
     ]
   }
 }