governance + unit-self-describing demand + dashboard fixes

Two governance items from the 2026-05-14 quality review:
- test/_output-manifest.md enumerates every Port 0/1/2 key MGC emits, its
  source, type, range, and which tests cover it in populated/degraded states
  (per .claude/rules/output-coverage.md).
- src/control/strategies.js extracts computeEqualFlowDistribution as a pure
  function so the equal-flow algorithm is testable without an MGC fixture.
  test/basic/equalFlowDistribution.basic.test.js (6 tests) covers all three
  demand branches and pins the legacy quirk where the default branch counts
  active machines but iterates priority-ordered first-N (documented in the
  test so the future cleanup is a deliberate change).

Plus rolled-up session work that landed alongside:
- set.demand is now unit-self-describing ({value, unit:'m3/h'|'l/s'|'%'|...}
  or bare number = %); setScaling/scaling.current removed from MGC, commands,
  editor (mgc.html), specificClass.
- _optimalControl + equalFlowControl now compute eta = (Q*dP)/P_shaft rather
  than Q/P, keeping the metric in the same scale as each child's cog.
- groupEfficiency.calcRelativeDistanceFromPeak returns undefined (was 1) when
  pumps are homogeneous (|max-min| < 1e-9). Dashboard treats undefined as
  '-' instead of showing a misleading 100% / 0% reading.
- examples/02-Dashboard.json: auto-init inject so the dashboard populates at
  deploy, NCog formatter normalizes the SUM emitted by MGC by
  machineCountActive, Q-H fanout trims the flat-Q tail so the H axis isn't
  stretched to 40m by curve-envelope clamp points, num/pct treat null AND
  undefined as no-data (closes the +null === 0 trap).
- new test/integration/dashboard-fanout.integration.test.js (17 tests),
  bep-distance-demand-sweep.integration.test.js (3 tests),
  group-bep-cascade.integration.test.js -- total suite now 108/108 green.
- .gitignore: wiki/test.gif (143 MB screen recording, kept locally only).

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

src/efficiency/groupEfficiency.js

@@ -44,19 +44,25 @@ class GroupEfficiency {
     }
 
     // Maps current efficiency onto [0..1] across [maxEfficiency..minEfficiency].
-    // Degenerate case (max === min) collapses the band to a point — return 1.
+    // Returns undefined for any case where the metric is meaningless:
+    //   - currentEfficiency missing
+    //   - the [max..min] band has collapsed (homogeneous pump group, OR float
+    //     noise so |max-min| < DEGENERATE_EPS).
+    // Consumers must treat undefined as "no data" and display accordingly,
+    // not as 0% / 100% — both readings would be misleading.
     calcRelativeDistanceFromPeak(currentEfficiency, maxEfficiency, minEfficiency) {
-        let distance = 1;
-        if (currentEfficiency != null && maxEfficiency !== minEfficiency && this.interpolation) {
-            distance = this.interpolation.interpolate_lin_single_point(
-                currentEfficiency,
-                maxEfficiency,
-                minEfficiency,
-                0,
-                1,
-            );
-        }
-        return distance;
+        const DEGENERATE_EPS = 1e-9; // η points are 0..1, so 1e-9 catches float noise.
+        if (currentEfficiency == null) return undefined;
+        if (!this.interpolation) return undefined;
+        if (!Number.isFinite(maxEfficiency) || !Number.isFinite(minEfficiency)) return undefined;
+        if (Math.abs(maxEfficiency - minEfficiency) < DEGENERATE_EPS) return undefined;
+        return this.interpolation.interpolate_lin_single_point(
+            currentEfficiency,
+            maxEfficiency,
+            minEfficiency,
+            0,
+            1,
+        );
     }
 
     // Returns both abs + rel; orchestrator decides whether to mirror onto