Fix J detach/re-parent on an already-nested sub-coordinator (#814 follow-up)

[anutron]

Problem

PR #814 added the — Detach (make top-level) — sentinel to the J coordinator picker so an operator can un-nest a sub-coordinator. But it could not be triggered on the exact case it was built for: an already-nested sub-coordinator.

When coordinator C is nested under parent P (via ReparentCoordinator), the rail renders C as a worker "bridge" row in P — the bridging worker role IS C's coordinator (same multi-binding task) and no separate child orchestrator header is drawn (internal/tui/hera/rail.go bridge placement). So selecting the nested sub-coord yields a Selection whose Role.Kind == HeraKindWorker. heraCoordReparentTarget only returned ok for a coordinator-kind role row or a coordinator's own orchestrator header — it returned false for a worker row, so heraOpenAdopt fell through to the statusbar error "J: select a freelancer or a coordinator to adopt".

The asymmetry: you could nest a top-level coordinator (selected as its orchestrator header) but could not un-nest it (now a headerless worker-bridge row).

Fix

heraCoordReparentTarget now qualifies a third shape: a non-archived worker-kind role whose Selection.BridgeChildOrchID != 0 — the same field the Ctrl+D cascade already reads, stamped by Rail.Selection when the cursor rests on a bridge row. That worker row IS the bridged child's coordinator, so it resolves the child orchestrator id and routes the existing heraAdoptCoordinator path:

• Detach (the must-fix): the detach sentinel → DetachCoordinator(childOrchID).
• Re-parent (symmetry): picking a different parent → ReparentCoordinator against the child orch; cycles still rejected authoritatively (ReparentCoordinator rejects nesting under self/descendant).

Guards preserved:

• Only a bridge row qualifies (BridgeChildOrchID != 0) — a plain (non-bridging) worker is never misclassified and still surfaces the "select a freelancer or coordinator" feedback.
• Inert in remote mode (heraAdoptOps == nil).
• The coord-task hint uses the structural bridge task (roleReclaimTask → BridgeTaskID else live TaskID).

No op-layer change — DetachCoordinator/ReparentCoordinator already resolve everything from the child orchestrator id alone. No new keybinding; help modal / README unchanged.

Tests

• TestHeraCoordReparentTarget — bridge-worker row qualifies (returns the child orch id, bridge role name, bridge task); prefers BridgeTaskID; plain worker (==0) and archived bridge row do not qualify.
• TestSmoke_HeraDetachNestedBridgeThroughPicker — select the bridge-row shape, J, Enter on the detach sentinel → parent link gone (child top-level again), child's own coord binding intact.
• TestSmoke_HeraReparentNestedBridgeThroughPicker — re-parent the nested coord under a different parent through the picker.
• Existing coordinator-header / coordinator-role detach + re-parent tests unchanged (no regression).

OpenSpec

fix-detach-nested-bridge (archived in-PR): the hera-view J requirement now defines a coordinator selection to include a worker-bridge sub-coordinator row; delta merged into the base spec, folder moved to openspec/changes/archive/2026-06-25-fix-detach-nested-bridge/. openspec validate --all --strict passes (47/47).

make pre-pr

• build ✓ · vet ✓ · fmt-check ✓ · lint-pr ✓ (0 issues) · test-cover-gate ✓ (89.5% ≥ 88 floor, -race green)
• vuln reports 2 stdlib-only CVEs (net/textproto, crypto/x509 in go1.26.3) — advisory, matching CI's continue-on-error for the vuln step; no first-party code affected.

🤖 Generated with Claude Code

Co-Authored-By: Claude noreply@anthropic.com

[github-actions]

Merging this branch will decrease overall coverage

Impacted Packages	Coverage Δ	🤖
github.com/drn/argus/internal/tui	83.98% (-0.03%)	👎

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Coverage by file

Changed files (no unit tests)

Changed File	Coverage Δ	Total	Covered	Missed	🤖
github.com/drn/argus/internal/tui/heraactions.go	77.73% (+0.10%)	440 (+2)	342 (+2)	98	👍

Please note that the "Total", "Covered", and "Missed" counts above refer to code statements instead of lines of code. The value in brackets refers to the test coverage of that file in the old version of the code.

Changed unit test files

• github.com/drn/argus/internal/tui/heraactions_test.go