Repo is the install location; all scripts self-locate

Users now clone to a persistent ZFS pool and the repo stays in place.
No files are copied on install — the PREINIT hook points directly into
the clone. Scripts derive PATCH_DIR from their own path at runtime.

- install.sh: PATCH_DIR=$(dirname $0); register patch/apply.sh as
  PREINIT target; chmod only, no cp; update pipe-install error message
- patch/apply.sh: PATCH_DIR=$(dirname $0)/..; substitute PATCH_DIR
  into sitecustomize.py via sed when writing to site-packages;
  reference patch_ui.py as patch/patch_ui.py
- recover.sh, uninstall.sh: PATCH_DIR=$(dirname $0)
- uninstall.sh: look for patch/apply.sh in PREINIT registry
- patch/create_task.py: _PATCH_DIR derived from __file__; apply.log
  path in error message derived from _PATCH_DIR
- patch/sitecustomize.py: /data/truecloud-patch remains as placeholder
  substituted by apply.sh on each install
- .gitignore: exclude runtime files (apply.log, hook_status.json, disabled)
- README: document clone-to-pool install; update all example paths

uninstall.sh

@@ -3,7 +3,7 @@
 
 set -euo pipefail
 
-PATCH_DIR="/data/truecloud-patch"
+PATCH_DIR="$(cd "$(dirname "$0")" && pwd)"
 
 echo "=== TrueNAS TrueCloud Provider Patch — Uninstall ==="
 echo ""
@@ -26,7 +26,7 @@ IDS=$(midclt call initshutdownscript.query '[]' | \
     python3 -c "
 import sys, json
 for s in json.load(sys.stdin):
-    if s.get('script') == '/data/truecloud-patch/apply.sh':
+    if s.get('script') == '$PATCH_DIR/patch/apply.sh':
         print(s['id'])
 " 2>/dev/null || true)