bd export omits parent-to-child dependency rows

[Jonathan-A-White]

Bug

bd export only includes dependency rows where the exported issue is the child (issue_id). Dependencies where the exported issue is the parent (depends_on_id) are silently dropped.

This means a bd push / bd pull roundtrip loses parent-to-child relationships in epic trees. The child→parent direction survives, but the parent→child direction does not.

Root cause

In cmd/bd/export.go, the dependency population loop only indexes by issue_id:

for _, issue := range issues {
    issue.Dependencies = allDeps[issue.ID]  // only child→parent direction
}

GetAllDependencyRecords returns dependencies keyed by issue_id, so any row where the issue is the depends_on_id (i.e. it's the parent) is never attached to that issue's export.

Impact

• Epic trees exported via bd export or bd push lose their parent→child edges
• bd pull on the receiving end sees fewer dependencies than the source
• Affects any workflow relying on JSONL roundtrip fidelity (multi-agent sync, backup/restore)

Fix

Build a reverse index (parentDeps[dep.DependsOnID]) and populate both directions when attaching dependencies to issues before export.

Fix: #1927

[steveyegge]

Closing: JSONL import/export plumbing has been removed — beads is now Dolt-native only. See 1e1568fa (remove JSONL plumbing), 6911eeaf (remove JSONL bootstrap), 01500d78 (remove cross-rig JSONL flush). This issue is no longer applicable.