Explain why start did nothing when a process is below its quantity

[facundofarias]

Problem

Supervisor#start_processes skips any process type that already has running instances, so a type running 23 of a configured 25 is skipped entirely:

$ procodile start -p worker
No processes to start.

$ procodile status
 * worker only has 23 instances (should have 25)

Two commands contradicting each other, with nothing pointing at check_concurrency as the one that actually tops the type up.

Change

Behaviour and the existing message are unchanged. When the supervisor is reporting an incorrect quantity for a type the user asked to start, the reason and remedy follow it:

No processes to start.
worker is running below the configured quantity.
Run `procodile check_concurrency` to start the missing process(es).

Notes

• The quantity lookup is a status call from the CLI — no change to the control protocol or to start_processes.
• It is advisory only, and wrapped so that a failure to read status cannot turn a successful no-op into an error.
• Requested instance names (worker.1) are reduced to their process type before matching.

Specs in spec/specs/cli_spec.rb cover the filtering logic. Full suite green (40 examples).