Assessment: 🟢 APPROVE

The two changes in this PR are both correct:

1. parser_flowchart.go — Removing the global dedup guard is intentional and correct. The old guard prevented a node from being assigned to a second subgraph even when the Mermaid source explicitly placed it there (a valid pattern). The stack-based logic already ensures a node is only added to the current innermost subgraph; appendUniqueMermaid correctly deduplicates within that subgraph's slice.

2. render_subgraph.go — The right bound arithmetic is correct. With rightBorder = " │" the rendered column layout is: before(W cols) + │(1) + (1) + text(T) + (1) + │(1). Setting x = W+2 (start of text) and right = x + T + 1 = W+T+3 lands exactly on the right border character │, matching what drawMermaidSubgraphBox expects.