revert(metacognitive-guard): remove session observer Stop hook (#147)

Prompt hooks on Stop only accept {decision, reason} — no additionalContext,
no systemMessage. Every other JSON field fails validation. The Stop event
is a gate (continue/stop), not a context injector.

Lesson learned: only PreToolUse, PostToolUse, UserPromptSubmit, and
SessionStart support additionalContext. Stop/SubagentStop are binary.

Co-authored-by: Claude Opus 4.6 <noreply@anthropic.com>

Author: ANcpLua

.claude-plugin/marketplace.json

@@ -11,7 +11,7 @@
     {
       "name": "metacognitive-guard",
       "description": "Cognitive amplification stack: epistemic hooks, competitive review, commit integrity checks, CI verification scripts, and deep-thinking agents.",
-      "version": "0.4.4",
+      "version": "0.4.5",
       "source": "./plugins/metacognitive-guard"
     },
     {

plugins/metacognitive-guard/.claude-plugin/plugin.json

@@ -1,7 +1,7 @@
 {
   "name": "metacognitive-guard",
   "description": "Cognitive amplification stack: epistemic hooks, competitive review, commit integrity checks, CI verification scripts, and deep-thinking agents.",
-  "version": "0.4.4",
+  "version": "0.4.5",
   "author": {
     "name": "AncpLua",
     "url": "https://github.com/ANcpLua"

plugins/metacognitive-guard/hooks/hooks.json

@@ -59,17 +59,6 @@
             "statusMessage": "Evaluating response quality..."
           }
         ]
-      },
-      {
-        "hooks": [
-          {
-            "type": "prompt",
-            "model": "haiku",
-            "prompt": "You are a silent session observer. You see Claude's latest response. Extract what was just accomplished and what appears to remain. Output ONLY valid JSON: {\"systemMessage\":\"SESSION: [done] → [in progress] → [remaining]\"}. Keep the systemMessage under 30 words. If the response is trivial (greeting, short answer, single question), return {}.",
-            "timeout": 10,
-            "statusMessage": "Session observer..."
-          }
-        ]
       }
     ],
     "PostToolUse": [