chore(caveman): purge plugin + always-on integration

Disable + uninstall caveman@caveman and delete every repo dependency on
it: SessionStart/UserPromptSubmit hook blocks, standalone hook files,
settings.json enabledPlugins + marketplace entries, install-plugins.sh
STEP 5.5, update-all.sh refresh step, plugins.lock.json entry, doctor.sh
checks, lib/detect-plugins.sh helpers, lib/profile.sh + plugin-advisor +
skills/profile protected-list entries, .gitignore runtime-file block,
and README/USAGE docs. Dead /caveman:compress refs replaced with
manual/claude.ai guidance. Memory-registry terse-format convention kept
(separate subsystem). Version 3.4.0 -> 3.5.0.

On a subscription plan caveman's ~75% output-token compression has no
cost benefit, and the always-on hooks added friction on validation
gates and client deliverables.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01X3e8LaH2vymmxyh36h3jFU

settings.json

@@ -195,16 +195,6 @@
             "command": "bash ~/.claude/hooks/session-start.sh"
           }
         ]
-      },
-      {
-        "hooks": [
-          {
-            "type": "command",
-            "command": "node ~/.claude/hooks/caveman-activate.js",
-            "timeout": 5,
-            "statusMessage": "Loading caveman mode..."
-          }
-        ]
       }
     ],
     "PreToolUse": [
@@ -219,16 +209,6 @@
       }
     ],
     "UserPromptSubmit": [
-      {
-        "hooks": [
-          {
-            "type": "command",
-            "command": "node ~/.claude/hooks/caveman-mode-tracker.js",
-            "timeout": 5,
-            "statusMessage": "Tracking caveman mode..."
-          }
-        ]
-      },
       {
         "hooks": [
           {
@@ -248,7 +228,6 @@
   "enabledPlugins": {
     "example-skills@anthropic-agent-skills": false,
     "ui-ux-pro-max@ui-ux-pro-max-skill": true,
-    "caveman@caveman": true,
     "security-guidance@claude-code-plugins": true,
     "superpowers@superpowers-marketplace": true,
     "pr-review-toolkit@claude-code-plugins": true
@@ -277,12 +256,6 @@
         "source": "github",
         "repo": "anthropics/skills"
       }
-    },
-    "caveman": {
-      "source": {
-        "source": "github",
-        "repo": "JuliusBrussee/caveman"
-      }
     }
   },
   "effortLevel": "xhigh",