Add a version check that runs before database migrations to ensure
users do not skip minor versions or downgrade. This protects database
migrations and allows future cleanup of old migration code.
Rules enforced:
- Same minor version: always allowed (patch changes either way)
- Single minor upgrade (e.g. 0.27 -> 0.28): allowed
- Multi-minor upgrade (e.g. 0.25 -> 0.28): blocked with guidance
- Any minor downgrade: blocked
- Major version change: blocked
- Dev builds: warn but allow, preserve stored version
The version is stored in a purpose-built database_versions table
after migrations succeed. The table is created with raw SQL before
gormigrate runs to avoid circular dependencies.
Updates #3058
This PR changes tags to be something that exists on nodes in addition to users, to being its own thing. It is part of moving our tags support towards the correct tailscale compatible implementation.
There are probably rough edges in this PR, but the intention is to get it in, and then start fixing bugs from 0.28.0 milestone (long standing tags issue) to discover what works and what doesnt.
Updates #2417Closes#2619
