chore: add clean onboarding test scripts

Scripts to test onboarding from scratch in isolated temp directories —
one via git clone + pnpm, one via npx from npm registry.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

scripts/clean-onboard-git.sh

@@ -0,0 +1,14 @@
+#!/bin/bash
+export PC_TEST_ROOT="$(mktemp -d /tmp/paperclip-clean.XXXXXX)"
+export PC_HOME="$PC_TEST_ROOT/home"
+export PC_CACHE="$PC_TEST_ROOT/npm-cache"
+export PC_DATA="$PC_TEST_ROOT/paperclip-data"
+mkdir -p "$PC_HOME" "$PC_CACHE" "$PC_DATA"
+echo "PC_TEST_ROOT: $PC_TEST_ROOT"
+echo "PC_HOME: $PC_HOME"
+cd $PC_TEST_ROOT
+git clone github.com:paperclipai/paperclip.git repo
+cd repo
+pnpm install
+env HOME="$PC_HOME" npm_config_cache="$PC_CACHE" npm_config_userconfig="$PC_HOME/.npmrc" \
+  pnpm paperclipai onboard --yes --data-dir "$PC_DATA"