100: Add Perps collateral, leverage, value, uPnL and gross-exposure totals in EMC

openspec/specs/evelyn-perps-overview/spec.md

@@ -67,3 +67,25 @@ Tooltips SHALL explain isolated collateral, exposure-based leverage, collateral-
 - **WHEN** the owner inspects a Cross row and its account group
 - **THEN** the position shows a USD margin requirement and the account shows shared capital once
 - **AND** no position-only metric is labeled account utilization
+
+### Requirement: Venue visibility follows available child rows
+EMC SHALL hide venue rows with neither positions nor Cross accounts and show them when children reappear. Funded empty Cross accounts SHALL keep their venue visible. Hidden venues SHALL remain in snapshots and totals, with read status available in wallet tooltips. Unknown scopes SHALL NOT become zero totals; failed reads SHALL preserve last-success totals. Wallet rows and the root SHALL remain visible.
+
+#### Scenario: Empty venue
+- **WHEN** Jupiter or Phoenix has no positions and no Cross accounts
+- **THEN** its heading is absent from that wallet's displayed children
+- **AND** a successful empty scope still contributes zero to totals
+
+#### Scenario: Funded Cross account without positions
+- **WHEN** Phoenix returns a Cross account with capital but no open positions
+- **THEN** Phoenix and its Cross account remain visible with that capital counted once
+
+#### Scenario: Positions disappear and return
+- **WHEN** a venue loses its last child and later returns a position
+- **THEN** its heading disappears and reappears with the correct child
+- **AND** unrelated retained rows keep their selection and expansion state
+
+#### Scenario: Hidden scope has not been read successfully
+- **WHEN** a childless venue has never been read successfully and its first read is pending or failed
+- **THEN** the heading is hidden and its read status is available on the wallet tooltip
+- **AND** required totals remain unavailable rather than reporting zero