feat(check): security value, commit tables, MEDUSA install and kvb-think-choice

kvb-check-security gains security.py: it scans the changed files with MEDUSA, weights findings (critical -50, high -25, medium -10, low -2) and prints locations and counts only; without MEDUSA it asks for a review by hand passed as '~<n>'. kvb-check-score takes --security and --critical: the score multiplies by security/100, a critical finding blocks the commit (exit 4), security below 100 asks the operator like efficiency or speed over 100, and a 90/5 failure now lists every cause. --table and --commit-table print the values as markdown tables, shown before and after every commit.

make install installs MEDUSA with pipx unless it is on the PATH. The new kvb-think-choice skill offers open decisions as multiple choice and checkboxes.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

scripts/install.sh

@@ -73,6 +73,15 @@ if [[ "${TARGET}" == "${HOME}" ]]; then
 	else
 		warn "skills: codebase-memory-mcp is not runnable from PATH; the code graph stays off (see kvb-agent-optimize)."
 	fi
+	if command -v medusa &>/dev/null; then
+		log "skills: the MEDUSA security scanner is installed"
+	elif ! command -v pipx &>/dev/null; then
+		warn "skills: pipx not found; install the MEDUSA scanner with 'pip install --user medusa-security'. Until then kvb-check-security reviews by hand."
+	elif pipx install medusa-security; then
+		log "skills: installed the MEDUSA security scanner for kvb-check-security"
+	else
+		warn "skills: the MEDUSA install failed; kvb-check-security reviews by hand."
+	fi
 fi
 
 log "skills: done. Restart your agent to load the skills."