Introduces the `administrators` relational table and repository layer
for the v3 backend, unifying instance, organization, project, and
project-grant membership into a single scoped model.
Closes#10220
## Changes
- **Domain**: `Administrator` struct, `AdministratorScope` enum,
`AdministratorRepository` interface with typed CRUD, column, condition,
and change helpers. Generated enumer and GoMock.
- **Migration** (`016`): `zitadel.administrators` table with a generated
`id`, scope-alignment check constraint, cascading foreign keys, and a
child `administrator_roles` table.
- **Repository**: CTE-based role mutations (`AddRole`, `RemoveRole`,
`SetRoles`) for atomicity. Roles aggregated via `ARRAY_AGG`.
- **Projection**: Event reducers for
`member.added/changed/removed/cascade_removed` across all four admin
scopes.
- **Fixes**: `Rows.Close()` error wrapping; `TextArray` nil-safe scan +
full `pgtype` array interface; `authorization` and `projectGrant` scan
helpers fixed for `ARRAY_AGG` under `database/sql`; removed unused `ctx`
parameter from `callReduce`.
---------
Co-authored-by: Marco Ardizzone <[email protected]>
## Problem description
During tests we found concurrency issues in the relational table
projections. Tests got flaky if a table (e.g. organization domains) had
too many foreign keys to tables which were projected by another handler.
## Resolution
The projections of the relational tables got merged into one handler to
enforce sequential reduction of events.
## Additional info
- closes https://github.com/zitadel/zitadel/issues/11703
- closes https://github.com/zitadel/zitadel/issues/10810
---------
Co-authored-by: Marco Ardizzone <[email protected]>
# Which Problems Are Solved
This PR provides an example for testing DB reduction to relational
tables without exploiting integration tests.
# How the Problems Are Solved
- Set up a disposable embedded Postgres DB used to store the results of
the calls to the reducers and verify such results
- Add utility method to return transactions from the existing DB pool.
These transactions can be used by the single test cases to insert and
read data from DB
- Add a test to verify that the handler contains the expected reducers
(checking also that they are on the right aggregate type)
- Add tests to verify the single reduce functions. A parent test creates
the required objects to satisfy the foreign key constraints.
# Additional Changes
- Typo fixed in `postgres.DecodeConfig()`
- Discard unneeded `projectionName` parameter for `Executor` function
# Additional Context
- Closes#11430
