Add MS_SimpleExport bot + hardened Linux export-runner

MS_SimpleExport is a market-data exporter (M1/Tick -> zipped binary), driven
headless via the official cTrader-console Docker image. This adds the bot and a
hardened bash driver that runs the scrape on a Linux host, spawning one ephemeral
console container per backtest window.

- src/MS_SimpleExport: the cBot; csproj aligned to the repo's Linux template
  (AlgoPublish=false, cTrader.Automate 1.*-*).
- scripts/export-runner.sh: hardened port of the Unraid driver -- retry-then-abort
  on transient failure, gap-aware resume, current-month end-date clamp, 3-way run
  classification with a per-run timeout, and ZIP validation before rename.
- scripts/export.env.example: deployment config template (real values live in the
  gitignored runtime/export.env).
- docs/export-runner-quirks.md: the multi-lens audit findings and hardening decisions.
- .gitignore: ignore runtime/ (secrets, the placed .algo, the symbol list).

.gitignore

@@ -11,3 +11,7 @@ dist/
 
 # Local tool installs
 .dotnet/
+
+# Deployment runtime: secrets (password.txt), the placed .algo, the symbol list,
+# and the credentials env file. Never commit any of this.
+runtime/