docs(locks): document cross-lane named locks (D)

docs/superpowers/plans/2026-08-03-shipyard-parity-lanes.md

@@ -25,7 +25,7 @@ stronger is a separate design (§ Future).
 | **A3** | Stack detection + profile scaffolding | A2 | ✅ **done** 2026-08-04 |
 | **B** | Per-feature state + archive | — | planned |
 | **C** | Proof gallery | B | planned |
-| **D** | Cross-lane named locks | — | planned |
+| **D** | Cross-lane named locks | — | ✅ **done** 2026-08-04 |
 | **E** | `ship-feature` skill + QC agents | A2·B·C·D | planned |
 | **F** | Integrations (tracker / dev-QC / CI) | E | planned |
 
@@ -347,11 +347,11 @@ check fires instead of silently degrading.
 A1 ✅ ──▶ A2 ✅ ──▶ A3 ✅
                      │
 B ──▶ C ─────────────┼──▶ E ──▶ F
-D ────────────────────┘
+D ✅ ────────────────────┘
 ```
 
 B next (it blocks E, and its presets must be derived from the profiles
-actually written during A1/A2). B, C, D are independent of the A chain and of
+actually written during A1/A2). B, C are independent (D done) of the A chain and of
 each other except C→B — take D first if the pain right now is lanes thrashing
 the machine, B first if it is `clear` erasing history.