Use platform for build environment names

[mr-cal]

What needs to get done

Change the instance naming convention from:

<app>-<project>-on-<build-on>-for-<build-for>-<project-dir-inode>

to:

<app>-<project>-<platform>-<project-dir-inode>

Why it needs to get done

To avoid the same instance getting used for different builds.

Example

Currently, these use the same build environment:

platforms:
  noble:
      build-on: amd64
      build-for: amd64
  noble-debug:
      build-on: amd64
      build-for: amd64

This is also a problem for multi-base recipes (canonical/charmcraft#2058).

[syncronize-issues-to-jira]

Thank you for reporting your feedback to us!

The internal ticket has been created: https://warthogs.atlassian.net/browse/CRAFT-3859.

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[syncronize-issues-to-jira]

Thank you for reporting your feedback to us!

The internal ticket has been created: https://warthogs.atlassian.net/browse/CRAFT-3858.

This message was autogenerated