Add simulator replica, persistence, planet scan, README; split empire state out of the repo

- tools/simulate.py + puga/simulate.py: replica of PRUNplanner's simulator (flows and
  efficiency verified against screenshots), reports real new capex (planned minus built)
- tools/scan.py: staffing variants, freight, HQ/experts, --planet mode, demolish-later,
  --min-n as a pure market-size filter, --json output
- tools/history.py, tools/persistence.py: margin history and short-horizon payback checks
- tools/plan_push.py: guarded delete; tools/state.py: syncs to empire/
- README with features and setup; CLAUDE.md made generic
- Own-empire material (profile, state, plans, notes) moved to gitignored empire/;
  generic examples in plans/examples and state/company.example.yaml

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>

.env.example

@@ -1,7 +1,8 @@
 # Copy to .env (gitignored, chmod 600) and fill in. Never paste keys into chat; edit the file.
-FIO_USERNAME=dodox
+FIO_USERNAME=
 FIO_REST_KEY=        # FIO REST key (rest.fnar.net authenticated endpoints)
 FIO_API_KEY=         # FIO API key (same as the FIO web account key); separate from REST, possibly a separate account
 PRUNPLANNER_API_KEY= # api.prunplanner.org key, sent as "Authorization: Api-Key <key>"
+COMPANY_CODE=
 DEFAULT_CX=AI1
 DEFAULT_REGION=antares