MGS5001: near-duplicate services

Two or more long-running service ops in the resolved run look like copies of the same service: they share an image repository and a container port, but differ in some detail (an environment variable, an image tag, a volume), so magus will not silently merge them. Left as-is they run as separate processes.

[MGS5001] 3 services share image "postgres" on container port 5432 but will run as separate processes:
  billing/db  (tag=15, POSTGRES_DB=billing)
  search/pg   (tag=16, POSTGRES_DB=search)
  web/api-db  (tag=15, POSTGRES_DB=api)
if these are meant to be one shared service, extract a shared target both need; otherwise mark them distinct with a reason.
  see: .../MGS5001.md

Why

When several projects each define "their own" Postgres (or app), each service is a distinct target, nothing deduplicates them, and bringing up the whole stack runs one process per project. That is the sprawl foot-gun: a machine drowning in near-identical, resource-hungry containers nobody meant to run separately.

Magus deduplicates services by a fingerprint of their configuration. Two services with an identical fingerprint are auto-shared silently. But these services are only nearly identical, and the difference may be load-bearing (a different POSTGRES_DB means a different database), so magus refuses to merge them on its own and surfaces them to you instead.

The comparison is deliberately conservative: the container port is the identity ("5432 means Postgres") while the host-port binding and the image tag are ignored for grouping, so version skew (postgres:15 vs postgres:16) still clusters and is reported as a difference rather than hidden. Services on different container ports are treated as intentionally separate and are not flagged at run time (they appear only in the magus doctor audit).

Fix

• If they are meant to be one instance, extract a single shared service target and have each project magus\needs it, so the dependency graph runs it once.
• If the difference is intentional (for example, a test that pins a different Postgres major version), mark the service distinct with a reason so the warning stays meaningful and the decision is auditable.