fix(security): harden auth, tenant scoping, and scrub secrets

Require session on APIs, scope KPIs/activos/simulate to the user tenant, strip real JWTs from .env.example, and add health/smoke/docs for 4Ventures ops.

Co-authored-by: Cursor <cursoragent@cursor.com>

.gitignore

@@ -0,0 +1,28 @@
+# dependencies
+node_modules/
+.pnp
+.pnp.js
+
+# next
+.next/
+out/
+build/
+dist/
+
+# env & secrets — never commit
+.env
+.env.*
+!.env.example
+
+# debug / OS
+npm-debug.log*
+yarn-debug.log*
+yarn-error.log*
+.DS_Store
+*.pem
+.vercel
+
+# local
+*.local
+coverage/
+.turbo/