fix(cli,mine): shell-quote project_dir in resume hints

The "Skipped. Run mempalace mine <dir>" hint after declining the init
prompt and the "Re-run mempalace mine <dir> to resume" hint after a
Ctrl-C interruption both interpolated project_dir without shell-quoting.
A path containing spaces or metacharacters produced a copy-paste-broken
command.

Both spots now use shlex.quote(project_dir). Adds regression tests
covering each hint with a path that contains a space.

mempalace/cli.py

@@ -238,7 +238,7 @@ def _maybe_run_mine_after_init(args, cfg) -> None:
             # we don't block. User can re-run with --auto-mine to opt in.
             answer = "n"
         if answer not in ("", "y", "yes"):
-            print(f"\n  Skipped. Run `mempalace mine {project_dir}` when ready.")
+            print(f"\n  Skipped. Run `mempalace mine {shlex.quote(project_dir)}` when ready.")
             return
 
     palace_path = cfg.palace_path

mempalace/miner.py

@@ -9,6 +9,7 @@ Stores verbatim chunks as drawers. No summaries. Ever.
 
 import os
 import sys
+import shlex
 import hashlib
 import fnmatch
 from pathlib import Path
@@ -1103,7 +1104,7 @@ def mine(
         print(f"    drawers_filed:   {total_drawers}")
         print(f"    last_file:       {last_file or '<none>'}")
         print(
-            f"\n  Re-run `mempalace mine {project_dir}` to resume — "
+            f"\n  Re-run `mempalace mine {shlex.quote(project_dir)}` to resume — "
             "already-filed drawers are\n  upserted idempotently and will not duplicate.\n"
         )
         sys.exit(130)