feat(uninstall): one-command full uninstall with confirmation

- uninstall.sh: removes pi-kit from settings.json (string + gated object
  entries), the package clone, kit-installed public skills, ~/.config/pi-kit
  (env.sh with tokens, audit.jsonl) and the shell-rc sourcing block
- confirmation prompt by default; PI_KIT_UNINSTALL=1 for non-interactive,
  PI_KIT_KEEP_CONFIG=1 / PI_KIT_KEEP_SKILLS=1 to retain parts
- works without the pi binary (settings edited directly); notes how to
  remove pi itself
- tests: test/uninstall.test.sh against a throwaway $HOME (14 checks:
  full/partial removal, refusal without flag, idempotent re-run), wired
  into npm test

test/uninstall.test.sh

@@ -0,0 +1,99 @@
+#!/usr/bin/env bash
+# Tests for uninstall.sh against a throwaway $HOME (no real machine state touched).
+# Run via `npm test` or directly: bash test/uninstall.test.sh
+set -euo pipefail
+
+ROOT="$(cd "$(dirname "$0")/.." && pwd)"
+UNINSTALL="$ROOT/uninstall.sh"
+FAILS=0
+
+check() { # <name> <bash-expression>
+	local name="$1"
+	if bash -c "$2"; then
+		echo "PASS  $name"
+	else
+		echo "FAIL  $name"
+		FAILS=$((FAILS + 1))
+	fi
+}
+
+# Fresh fake home with everything the kit can leave behind.
+setup_fake_home() {
+	export HOME="$(mktemp -d)"
+	export SHELL=/bin/bash
+	export PI_KIT_UNINSTALL=1
+	export PI_KIT_KEEP_CONFIG=0
+	export PI_KIT_KEEP_SKILLS=0
+
+	mkdir -p "$HOME/.pi/agent/git/git.codelab.vc/ai/pi-kit"
+	mkdir -p "$HOME/.agents/skills"
+	mkdir -p "$HOME/.config/pi-kit"
+
+	cat >"$HOME/.pi/agent/settings.json" <<'JSON'
+{
+  "packages": [
+    "git:github.com/someone/other",
+    { "source": "git:git.codelab.vc/ai/pi-kit@stable", "skills": ["skills/go-standards"] },
+    "git:git.codelab.vc/ai/pi-kit@beta"
+  ]
+}
+JSON
+	echo "export JIRA_TOKEN='dummy'" >"$HOME/.config/pi-kit/env.sh"
+	cat >"$HOME/.agents/skills/grill-me" <<'EOF'
+skill content
+EOF
+	cat >"$HOME/.bashrc" <<'RC'
+# user content
+export FOO=1
+
+# >>> pi-kit >>>
+[ -f "$HOME/.config/pi-kit/env.sh" ] && . "$HOME/.config/pi-kit/env.sh"
+# <<< pi-kit <<<
+
+# more user content
+RC
+}
+
+# --- 1. Full uninstall --------------------------------------------------------
+setup_fake_home
+bash "$UNINSTALL" >/dev/null
+check "uninstall: settings.json keeps other packages" "grep -q 'git:github.com/someone/other' \"$HOME/.pi/agent/settings.json\""
+check "uninstall: settings.json drops object-form pi-kit" "! grep -q 'pi-kit' \"$HOME/.pi/agent/settings.json\""
+check "uninstall: clone dir removed" "test ! -e \"$HOME/.pi/agent/git/git.codelab.vc/ai/pi-kit\""
+check "uninstall: config dir removed" "test ! -e \"$HOME/.config/pi-kit\""
+check "uninstall: rc block removed" "! grep -q 'pi-kit' \"$HOME/.bashrc\""
+check "uninstall: rc user content preserved" "grep -q 'export FOO=1' \"$HOME/.bashrc\" && grep -q 'more user content' \"$HOME/.bashrc\""
+check "uninstall: public skill removed" "test ! -e \"$HOME/.agents/skills/grill-me\""
+
+# --- 2. Keep config (secrets + rc) --------------------------------------------
+setup_fake_home
+PI_KIT_KEEP_CONFIG=1 bash "$UNINSTALL" >/dev/null
+check "keep-config: env.sh kept" "test -e \"$HOME/.config/pi-kit/env.sh\""
+check "keep-config: rc block kept" "grep -q 'pi-kit' \"$HOME/.bashrc\""
+check "keep-config: package still removed" "! grep -q 'pi-kit' \"$HOME/.pi/agent/settings.json\""
+
+# --- 3. Keep skills ------------------------------------------------------------
+setup_fake_home
+PI_KIT_KEEP_SKILLS=1 bash "$UNINSTALL" >/dev/null
+check "keep-skills: skill kept" "test -e \"$HOME/.agents/skills/grill-me\""
+
+# --- 4. Non-interactive without flag must refuse ---------------------------------
+setup_fake_home
+PI_KIT_UNINSTALL=0 bash "$UNINSTALL" >/dev/null 2>&1 && RC=0 || RC=$?
+check "uninstall: refuses without confirmation flag in non-interactive mode" "test \"$RC\" -ne 0"
+check "uninstall: nothing removed on refusal" "grep -q 'pi-kit' \"$HOME/.pi/agent/settings.json\" && test -e \"$HOME/.config/pi-kit/env.sh\""
+
+# --- 5. Idempotent re-run -------------------------------------------------------
+setup_fake_home
+bash "$UNINSTALL" >/dev/null
+bash "$UNINSTALL" >/dev/null 2>&1 || true
+check "uninstall: re-run is harmless" "test ! -e \"$HOME/.config/pi-kit\" && ! grep -q 'pi-kit' \"$HOME/.pi/agent/settings.json\""
+
+echo ""
+if [ "$FAILS" -eq 0 ]; then
+	echo "uninstall tests: ALL PASS"
+	exit 0
+else
+	echo "uninstall tests: $FAILS FAILED"
+	exit 1
+fi