Releasing one channel pause ignores another active hold

### Feature Summary

An input channel can be paused independently for more than one reason. Releasing one pause type currently enables the channel immediately, even when another pause type still holds the same channel. Tuples can therefore resume during an active embedded-control or debug pause.

Expected behavior: a channel remains disabled until its final hold is released.

Before: releasing one of two holds enables the channel

After: the channel stays disabled until both holds are released

Reproduction evidence:

Pause one registered channel with both `DEBUG_PAUSE` and `ECM_PAUSE`, then resume only `DEBUG_PAUSE`. The queue reports the channel as enabled while the ECM hold remains recorded.

Version and commit evidence:

1.3.0-incubating-SNAPSHOT on main

**Commit Hash (Optional)**
50321e403c82df299a13deb50a7f9849dd93bdba

**Browsers**

Not browser specific

**Relevant log output**

The ECM hold remains present while the channel is enabled.

### Proposed Solution or Design

Expected behavior: a channel remains disabled until its final hold is released.

After: the channel stays disabled until both holds are released

### Affected Area

Workflow Engine (Amber)