Symptom

The source picker in TargetingWiringEditor (and all executor editors) was hardcoded to three tabs: DataPoint, Pin, and LogicGate. Users had no way to wire any other node type as a source, and cross-server (peer) nodes were invisible in the picker even though ClientNodeManager already holds all connected peers’ nodes.

Root cause

SourceList in NodeList.kt enumerated its type list as a hardcoded listOf(KrillApp.DataPoint, KrillApp.Server.Pin, KrillApp.Executor.LogicGate) and never looked beyond the local host. The P2P architecture was fully in place in ClientNodeManager but the picker was never wired to use it.

Fix

Replaced the 3-tab SourceList with a two-step picker:

• Step 1: types derived from ClientNodeManager.nodes() — the live swarm contents, not a hardcoded list; nodes with state == DELETING excluded; sorted by KrillApp.title().
• Step 2: all non-DELETING nodes of the chosen type from all connected peers (ClientNodeManager already aggregates them), grouped by node.host. When more than one host contributes nodes of the selected type, a host-name header is shown per group (resolved from the host’s ServerMetaData.name). Each candidate row uses NodeSummaryAndEditor(node, ViewMode.ROW) so the picker stays visually consistent as per-type ROW composables evolve.
• Added existingSources: List<NodeIdentity> parameter to SourceList and SourceListWithBackNavigation; wired it into TargetingWiringEditor so already-wired nodes never appear as picker candidates.
• Extracted sourcePickerAvailableTypes and sourcePickerCandidates as internal pure functions in NodeList.kt so the filtering + grouping logic can be unit-tested without any Compose or network infrastructure.

Prevention

• Any hardcoded sublist of KrillApp subtypes in a picker warrants a comment explaining why the subset is correct. If the comment cannot be written, derive dynamically from the live swarm instead.
• sourcePickerCandidates is now tested for: DELETING exclusion, de-dupe against existingSources, cross-host inclusion, and host-qualified identity matching. Add tests here when extending the picker’s filter logic.
• The groupBy { it.host } idiom is the canonical cross-server grouping pattern; re-use it rather than inventing per-picker host logic.