docs: make environment examples safe and current (#6777)

* docs: make SQLite environment example runnable

* docs: remove unsafe source secret examples

* docs(auth): remove unsafe SSO environment values

* docs(auth): clarify OIDC credential placeholders

.env.example

@@ -1,22 +1,24 @@
 # Since .env is gitignored, you can use .env.example to build a new `.env` file when you clone the repo.
-# Keep this file up-to-date when you add new variables to \`.env\`.
+# Keep this file up-to-date when you add new variables to `.env`.
 
 # This file will be committed to version control, so make sure not to have any secrets in it.
 # If you are cloning this repo, create a copy of this file named `.env` and populate it with your secrets.
 
-# The below secret is not used anywhere but required for Auth.js (Would encrypt JWTs and Mail hashes, both not used)
-AUTH_SECRET="supersecret"
+# Generate two different 64-character hex values with `openssl rand -hex 32` before starting Homarr.
+# Never reuse these values or commit the populated `.env` file.
+AUTH_SECRET=
 
 # The below secret is used to encrypt integration secrets in the database.
-# It should be a 32-byte string, generated by running `openssl rand -hex 32` on Unix
-# or starting the project without any (which will show a randomly generated one).
-SECRET_ENCRYPTION_KEY=0000000000000000000000000000000000000000000000000000000000000000
+# Homarr will reject an empty or invalid value and print a randomly generated candidate.
+SECRET_ENCRYPTION_KEY=
 
 LOG_LEVEL='info'
 
 # This is how you can use the sqlite driver:
 DB_DRIVER='better-sqlite3'
-DB_URL='FULL_PATH_TO_YOUR_SQLITE_DB_FILE'
+# Safe local source-development path. SQLite files are ignored by Git.
+# Container images use /appdata/db/db.sqlite by default instead.
+DB_URL='./db.sqlite'
 
 # Those are the two ways to use the mysql2 driver:
 # 1. Using the URL format: