Replace placeholder passwords with concrete defaults in env.template

[Copilot]

The environment template contained placeholder strings like your_secure_password_change_this for passwords, requiring manual replacement before the application could run. This adds friction to initial setup and local development.

Changes

• PostgreSQL credentials: POSTGRES_PASSWORD, DB_PASSWORD, JWT_POSTGRES_DATABASE_PASSWORD → postgres
• Django admin: DJANGO_SUPERUSER_PASSWORD → admin
• Oxigraph SPARQL DB: OXIGRAPH_PASSWORD, GRAPHDATABASE_PASSWORD → admin
• pgAdmin: PGADMIN_DEFAULT_PASSWORD → admin
• JWT secret keys: Replaced generic placeholders with descriptive defaults
• Django secret key: Set to django-insecure-default-key-change-in-production

Added WARNING comments before credential sections to indicate these defaults must be changed for production deployments.

# Before
POSTGRES_PASSWORD=your_secure_password_change_this

# After
# WARNING: Change these default passwords in production!
POSTGRES_PASSWORD=postgres

Original prompt

---

This section details on the original issue you should resolve

<issue_title>SS-1: Setup some default passwords</issue_title>
<issue_description>

just make a default password in the environment file </issue_description>

Comments on the Issue (you are @copilot in this section)

• Fixes SS-1: Setup some default passwords #48

---

💬 We'd love your input! Share your thoughts on Copilot coding agent in our 2 minute survey.

[Sulstice]

@copilot Yes this is fine. just reduce annoyances.

[tekrajchhetri]

Closing this request.