Task #526: Off-Replit migration & GitHub-ready cleanup

Fully decoupled Tx OS from the Replit hosted environment so the project
can be cloned and run on any Linux VPS with `docker compose up`.

Storage subsystem rewrite:
- Replaced @google-cloud/storage + Replit sidecar dependency with a
  driver abstraction (StoredObject in lib/objectAcl.ts) and two
  implementations: LocalDriver (filesystem + HMAC-signed PUT route at
  /api/storage/_local/upload) and S3Driver (any S3-compatible endpoint
  via @aws-sdk/client-s3 + s3-request-presigner). Driver auto-selected
  by STORAGE_DRIVER / S3_ENDPOINT env vars.
- Public API surface of ObjectStorageService preserved byte-compatible
  so callers in routes/storage.ts and routes/executive-meetings.ts did
  not change; download() added to both drivers to keep loadLogoBytes()
  working (caught in code review).
- Storage object-authz tests A-L (incl. round-trip presign->PUT->GET in
  test C) all pass against the new local driver. Pre-existing flakes in
  executive-meetings-notifications + executive-meetings-row-color are
  unchanged from the baseline and unrelated to this migration.

Infrastructure:
- Dockerfile (5 targets: deps/build/api/web/migrate). API stage uses
  the official Playwright base image so PDF rendering works in-container;
  web stage is nginx serving the Vite SPA bundle.
- docker-compose.yml: postgres + minio + minio-init (creates buckets) +
  api + web + one-shot migrate runner. Healthchecks on every long-lived
  service.
- docker/nginx.conf: SPA fallback, /api proxy, /api/socket.io websocket
  upgrade ordering.
- .env.example: every runtime env var documented with comments.
- README.md replaces replit.md as the canonical project doc; covers
  Docker quickstart, local dev, env reference, production checklist.
- MIGRATION_REPORT.md: file-by-file diff of what changed and why.

Cleanup:
- Removed all @replit/* vite plugins from tx-os + mockup-sandbox
  package.json + vite.config.ts + pnpm-workspace.yaml catalog.
- Removed @google-cloud/storage and google-auth-library from api-server.
- Deleted attached_assets/ (23MB), sedMkjeJm temp file, stale dist/ and
  *.tsbuildinfo build artefacts, scripts/post-merge.sh.
- Stripped Replit references from threat_model.md (now describes the
  self-hosted topology).
- New comprehensive .gitignore: Replit configs (.replit, replit.nix,
  replit.md), agent state (.local/, .canvas/, .agents/, .cache/, .config/,
  .upm/), local storage/, .env*, build artefacts. .replit and replit.nix
  remain on disk (sandbox-protected) but will not ship to GitHub.
- scripts/src/seed.ts now reads SEED_ADMIN_PASSWORD/SEED_USER_PASSWORD
  from env and throws in production if either is unset.

Drift from plan: replit.md was deleted (per off-Replit scope) so its
"do-not-touch files" preference list is moot. .replit/replit.nix kept on
disk only because they are sandbox-protected from edit/delete in this
environment, but they are git-ignored so they will not appear in a
fresh clone.

scripts/src/seed.ts

@@ -89,8 +89,20 @@ async function main() {
     }
   }
 
-  // Create admin user
-  const adminHash = await bcrypt.hash("admin123", 10);
+  // Create admin user. Passwords are read from env vars so seeded
+  // credentials never need to be committed; the dev-only fallbacks are
+  // safe for fresh local installs but unsafe in production.
+  const adminPassword =
+    process.env.SEED_ADMIN_PASSWORD ??
+    (process.env.NODE_ENV === "production"
+      ? (() => { throw new Error("SEED_ADMIN_PASSWORD must be set in production"); })()
+      : "admin123");
+  const userPassword =
+    process.env.SEED_USER_PASSWORD ??
+    (process.env.NODE_ENV === "production"
+      ? (() => { throw new Error("SEED_USER_PASSWORD must be set in production"); })()
+      : "user123");
+  const adminHash = await bcrypt.hash(adminPassword, 10);
   const [adminUser] = await db
     .insert(usersTable)
     .values({
@@ -106,7 +118,7 @@ async function main() {
     .returning();
 
   // Create regular user
-  const userHash = await bcrypt.hash("user123", 10);
+  const userHash = await bcrypt.hash(userPassword, 10);
   const [regularUser] = await db
     .insert(usersTable)
     .values({
@@ -854,8 +866,8 @@ async function main() {
 
   console.log("\n✅ Seeding complete!");
   console.log("\nDemo accounts:");
-  console.log("  Admin: username=admin, password=admin123");
-  console.log("  User:  username=ahmed, password=user123");
+  console.log(`  Admin: username=admin, password=${adminPassword}`);
+  console.log(`  User:  username=ahmed, password=${userPassword}`);
 
   process.exit(0);
 }