The default _state_dir() used C:\\Users\\Ed\\AppData\\Local\\manual_slop\\tier2\\
which contradicted the user's 'NEVER USE APPDATA' directive (2026-06-18).
New default: scripts/tier2/state/<track>/ (Path.cwd()-relative). The
TIER2_STATE_DIR env-var override is preserved as an escape hatch.
The Tier 2 agent's CWD is always the clone root, so this resolves to
<clone>/scripts/tier2/state/<track>/state.json.
Refs: conductor/tracks/tier2_no_appdata_20260618
ed