Squashed commit of the following:

commit b1c1179a01e9aa924efc318a71593031ffc02701
Merge: 7a666537b d8f5a3a
Author: Hilary James Oliver <[email protected]>
Date:   Wed Jun 18 13:47:05 2025 +1200

    Merge branch 'group-trigger' of github.com:hjoliver/cylc-flow into group-trigger

commit d8f5a3a
Merge: a94b407 2b908e9
Author: Hilary James Oliver <[email protected]>
Date:   Wed Jun 18 13:45:15 2025 +1200

    Merge pull request #66 from oliver-sanders/group-trigger++

    group trigger: test removal of active tasks and response to graph changes

commit 7a666537b039159e2de835cd5caf4911c59b09f5
Merge: c83a7f9b1 3248ebe
Author: Hilary James Oliver <[email protected]>
Date:   Wed Jun 18 13:40:54 2025 +1200

    Merge branch 'master' into group-trigger

commit c83a7f9b16edffca34b7322946e2dc7ce2d218f3
Author: Hilary James Oliver <[email protected]>
Date:   Wed Jun 18 13:27:35 2025 +1200

    Tidy a bit.

commit ebff027cb015efbbe90815efe8493212f39ad092
Author: Hilary James Oliver <[email protected]>
Date:   Wed Jun 18 13:26:04 2025 +1200

    Fix small regression.

commit 2b908e9
Author: Oliver Sanders <[email protected]>
Date:   Mon Jun 16 16:31:21 2025 +0100

    group trigger: test removal of active tasks and response to graph changes

commit a94b407
Merge: b9561aa 4ed84b1
Author: Hilary James Oliver <[email protected]>
Date:   Tue May 20 16:37:18 2025 +1200

    Merge branch 'master' into group-trigger

commit b9561aa
Author: Hilary James Oliver <[email protected]>
Date:   Wed May 14 00:30:24 2025 +0000

    Replace group trigger functional test.

commit 78c3a2f
Author: Hilary James Oliver <[email protected]>
Date:   Tue May 13 01:07:07 2025 +0000

    Final branch tidy.

commit c71a47a
Author: Hilary James Oliver <[email protected]>
Date:   Fri May 9 17:31:14 2025 +1200

    Rephrase a log message.

commit 5e7f9ba
Author: Hilary James Oliver <[email protected]>
Date:   Fri May 9 15:50:04 2025 +1200

    Tidy prerequisite logging.

commit 5f9f8b9
Author: Hilary James Oliver <[email protected]>
Date:   Fri May 9 14:30:17 2025 +1200

    Handle a KeyError.

commit 922ad96
Author: Hilary James Oliver <[email protected]>
Date:   Fri May 9 13:13:47 2025 +1200

    Handle xtriggers in group trigger.

commit 596606c
Author: Hilary James Oliver <[email protected]>
Date:   Thu May 8 21:28:15 2025 +0000

    Tweak command help.

commit 3805e0d
Author: Hilary James Oliver <[email protected]>
Date:   Thu May 8 11:16:21 2025 +0000

    Post-rebase fix-ups.

commit c0d850e
Author: Hilary James Oliver <[email protected]>
Date:   Thu May 8 11:10:37 2025 +0000

    Add test TODO.

commit 791316b
Author: Hilary James Oliver <[email protected]>
Date:   Tue Apr 8 16:52:01 2025 +1200

    Redo trigger CLI help.

commit 8f1a097
Author: Hilary James Oliver <[email protected]>
Date:   Tue Apr 8 02:51:22 2025 +0000

    Squashed commit of the following:

    commit efe0a744ce3acf2e33344cc81ea039565b10a171
    Author: Hilary James Oliver <[email protected]>
    Date:   Tue Apr 8 02:50:47 2025 +0000

        Remove an unused method.

    commit e8a17d85ff8efe6ce166d4b6dc49b7786d10da69
    Author: Hilary James Oliver <[email protected]>
    Date:   Tue Apr 8 02:48:22 2025 +0000

        Update change log.

    commit 91e09f2
    Author: Hilary James Oliver <[email protected]>
    Date:   Tue Apr 8 01:27:18 2025 +0000

        Update a func test.

    commit cbc1050
    Merge: 0d9e089 50980d5
    Author: Hilary James Oliver <[email protected]>
    Date:   Tue Apr 8 12:58:28 2025 +1200

        Merge branch 'master' into group-trigger

    commit 0d9e089
    Author: Hilary James Oliver <[email protected]>
    Date:   Tue Apr 8 00:50:54 2025 +0000

        Add new unit test.

    commit 3668abe
    Author: Hilary James Oliver <[email protected]>
    Date:   Tue Apr 8 08:45:41 2025 +1200

        Minor tweaks.

    commit c522859
    Author: Hilary James Oliver <[email protected]>
    Date:   Tue Apr 8 08:37:14 2025 +1200

        Tweak change log entry.

    commit 7efc653
    Author: Hilary James Oliver <[email protected]>
    Date:   Mon Apr 7 17:45:06 2025 +1200

        Post merge fix.

    commit b002426
    Merge: 3c68193 9ed2014
    Author: Hilary James Oliver <[email protected]>
    Date:   Mon Apr 7 03:29:05 2025 +0000

        Merge branch 'master' into group-trigger

    commit 3c68193
    Author: Hilary James Oliver <[email protected]>
    Date:   Mon Mar 31 09:59:42 2025 +1300

        Tidy code. [skip ci]

    commit 9445328
    Author: Hilary James Oliver <[email protected]>
    Date:   Fri Mar 28 17:03:03 2025 +1300

        Squashed commit of group-trigger development.

    Tweak group trigger.

    tweak