feat(skills): support install preflight-only mode

docs/plans/state.json

@@ -1379,6 +1379,15 @@
               "src/cli/skills.test.ts"
             ],
             "test_status": "pnpm typecheck + pnpm test:run src/cli/skills.test.ts + pnpm test:run + pnpm lint (warnings only, 0 errors) + pnpm build passing"
+          },
+          "install_preflight_only_mode": {
+            "status": "completed",
+            "description": "Added --preflight-only mode to skills install for plan-only previews without performing installation, including JSON output path",
+            "files_modified": [
+              "src/cli/skills.ts",
+              "src/cli/skills.test.ts"
+            ],
+            "test_status": "pnpm typecheck + pnpm test:run src/cli/skills.test.ts + pnpm test:run + pnpm lint (warnings only, 0 errors) + pnpm build passing"
           }
         }
       }
@@ -1407,7 +1416,7 @@
   },
 
   "overall_progress": {
-    "total_test_count": 1528,
+    "total_test_count": 1529,
     "all_tests_passing": true,
     "p0_completion": "3/3 (100%)",
     "p1_completion": "4/4 (100%)",
@@ -1427,7 +1436,7 @@
     "gmail_auth_cli": "flynn gmail-auth command implemented with OAuth2 flow, doctor check, config routed to Telegram",
     "native_audio_support": "completed — smart routing for native audio (Gemini/OpenAI/GitHub) vs Whisper transcription fallback",
     "remaining_phases_completion": "Phase 1: 3/3 (100%) — context levels, command registry, memory structure. Phase 2: 2/2 (100%) — component registry, confidence routing. Phase 3: 2/2 (100%) — adaptive memory/compaction, truthfulness/autonomy hardening",
-    "next_up": "Skills infrastructure Phase 3: add install preflight-only mode to print plan without performing install"
+    "next_up": "Skills infrastructure Phase 3: add installer execution stub command that consumes plan output but does not run package manager commands yet"
   },
   "soul_md_and_cron_create": {
     "date": "2026-02-11",