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

plugins.lock.json

@@ -31,14 +31,5 @@
     "path": "skills/emil-design-eng/SKILL.md",
     "managed_by": "curl",
     "note": "Emil Kowalski's design engineering skill — UI polish, animations, component craft. Downloaded to skills-external/emil-design-eng/, symlinked by link.sh."
-  },
-  "caveman": {
-    "source": "https://github.com/JuliusBrussee/caveman",
-    "marketplace": "JuliusBrussee/caveman",
-    "plugin_ref": "caveman@caveman",
-    "managed_by": "claude plugin + standalone hooks installer + claude mcp",
-    "extras": ["hooks (statusline + stats)", "caveman-shrink MCP proxy"],
-    "version": "latest",
-    "note": "Caveman — ~75% output token compression via caveman-speak. Full install = plugin + standalone hooks (statusline + stats badge) + caveman-shrink MCP (input compression). Updates pull via 'claude plugin update'; hooks installer is idempotent."
   }
 }