Support structured database connection config as alternative to URL

[mikkeldamsgaard]

Summary

The seed spec currently requires database connections to be specified as a single url: string. This forces users to deal with URL encoding of credentials and makes seed specs harder to read. A structured config format would eliminate this class of issues entirely.

Problem

Building a connection URL in a template is fragile:

database:
  driver: postgres
  url: "postgres://user:{{ env.DB_PASSWORD }}@host:5432/mydb?sslmode=disable"

If the password contains URL-reserved characters (@, %, :, etc.), the URL breaks. Users must either:

• Percent-encode the password (see Register MiniJinja's built-in urlencode filter #38 for the urlencode filter request)
• Use driver-specific non-URL formats (e.g., PostgreSQL key-value DSN)

Both are workarounds for a problem that shouldn't exist — the user just wants to provide connection parameters.

Suggested Enhancement

Accept discrete connection fields as an alternative to url::

database:
  driver: postgres
  host: pg.example.com
  port: 5432
  user: netbird
  password: "{{ env.DB_PASSWORD }}"
  name: mydb
  options:
    sslmode: disable

Initium would construct the connection internally using the driver's native API (e.g., PgConnectOptions for PostgreSQL, MySqlConnectOptions for MySQL), bypassing URL parsing entirely. The url: field would remain supported for backward compatibility.

Benefits

• No encoding issues — passwords with any characters just work
• Readable — mirrors how Kubernetes operators and Helm charts typically express DB config
• Type-safe — invalid field names caught at parse time instead of silently producing a bad URL
• Driver-agnostic — Initium maps fields to whatever the driver needs; users don't need to know URL format differences between PostgreSQL and MySQL

Use Case

We hit this in the netbird Helm chart (issue #32). Our workaround is PostgreSQL key-value DSN + a chain of MiniJinja replace filters for MySQL. A structured config would let us drop both workarounds.