fix(paths): route achievements plugin + profile-tui through HERMES_HOME

Four callsites hardcoded Path.home() / '.hermes' with no HERMES_HOME
check, breaking Docker deployments and profile isolation (hermes -p):

- plugins/hermes-achievements/dashboard/plugin_api.py:
  state_path(), snapshot_path(), checkpoint_path() bare-literal paths
- scripts/profile-tui.py:
  DEFAULT_STATE_DB and DEFAULT_LOG defaults ignored HERMES_HOME
- hermes_cli/slack_cli.py:
  except-Exception fallback for slack-manifest.json dump
- optional-skills/migration/openclaw-migration/scripts/openclaw_to_hermes.py:
  --target argparse default

Use get_hermes_home() (with an ImportError shim for the standalone
scripts) or 'os.environ.get("HERMES_HOME") or str(Path.home()/".hermes")'
where importing hermes_constants is impractical.

E2E-verified: with HERMES_HOME=/tmp/x all three achievements paths and
both profile-tui defaults route under /tmp/x.

Salvaged from #18068 (original scope was broader mechanical cleanup
claiming 23 callsites were buggy; most were already respecting
HERMES_HOME via os.environ.get(key, default) — only these 4 had no env
check at all). Credit: @web-dev0521.

plugins/hermes-achievements/dashboard/plugin_api.py

@@ -12,6 +12,14 @@ import time
 from pathlib import Path
 from typing import Any, Dict, List, Optional, Set
 
+try:
+    from hermes_constants import get_hermes_home
+except ImportError:
+    import os as _os
+    def get_hermes_home() -> Path:  # type: ignore[misc]
+        val = (_os.environ.get("HERMES_HOME") or "").strip()
+        return Path(val) if val else Path.home() / ".hermes"
+
 try:
     from fastapi import APIRouter
 except Exception:  # Allows local unit tests without dashboard dependencies.
@@ -135,15 +143,15 @@ ACHIEVEMENTS: List[Dict[str, Any]] = [
 
 
 def state_path() -> Path:
-    return Path.home() / ".hermes" / "plugins" / "hermes-achievements" / "state.json"
+    return get_hermes_home() / "plugins" / "hermes-achievements" / "state.json"
 
 
 def snapshot_path() -> Path:
-    return Path.home() / ".hermes" / "plugins" / "hermes-achievements" / "scan_snapshot.json"
+    return get_hermes_home() / "plugins" / "hermes-achievements" / "scan_snapshot.json"
 
 
 def checkpoint_path() -> Path:
-    return Path.home() / ".hermes" / "plugins" / "hermes-achievements" / "scan_checkpoint.json"
+    return get_hermes_home() / "plugins" / "hermes-achievements" / "scan_checkpoint.json"
 
 
 def load_state() -> Dict[str, Any]: