chain table round 3: waypoints icons gone + the alignment staircase (owner refinements)

- chain rows lose the WaypointsIcon (owner: not needed — the chips +
  connectors already read as chains); folders keep their icons.
- THE ALIGNMENT STAIRCASE: every level's checkbox sits directly under
  its parent's expander arrow. The expander now shares the checkbox's
  14px width (h-5 w-3.5), making each nesting step exactly 18px —
  clusters pl-3 (12px) → chains pl-7.5 (30px, the cluster expander) →
  statements pl-12 (48px, the chain expander). Live-measured: 318=318,
  336=336.

tests/render-chain-table.test.tsx

@@ -139,9 +139,9 @@ describe("ChainTableBody — THE shared TopBar + the lines law (owner, round 2)"
 		const sep = html.split("border-b border-border/60").length - 1;
 		assert.ok(sep >= 2, "separators between groups");
 		// chain rows themselves carry NO border — their entire class list is
-		// the indent law (pl-11 under the cluster folder, owner round 2); the
-		// chip outlines' border-border/70 is an outline, not a row line
-		assert.ok(html.includes('class="flex items-center gap-1 py-1 pl-11 pr-3"'), "the chain row: indent, no border");
+		// the staircase law (pl-7.5 = under the cluster's expander arrow);
+		// the chip outlines' border-border/70 is an outline, not a row line
+		assert.ok(html.includes('class="flex items-center gap-1 py-1 pl-7.5 pr-3"'), "the chain row: staircase indent, no border");
 	});
 });
 
@@ -154,7 +154,9 @@ describe("ChainTableBody — chain rows (chips + connectors)", () => {
 		assert.ok(html.includes("Premise one"), "chip text");
 		assert.ok(html.includes('data-testid="chain-arrow-c1-1"'), "the connector");
 		assert.ok(html.includes("→"), "the arrow glyph");
-		assert.ok(html.includes("lucide-waypoints"), "the chain icon");
+		// owner ruling (round 3): the chain waypoints icons are GONE — the
+		// chips + connectors already read as chains; only folders keep icons
+		assert.ok(!html.includes("lucide-waypoints"), "no chain icon");
 	});
 
 	it("a singleton renders ONE lonely chip, no connector; the annotation survives only for screen readers", () => {
@@ -184,9 +186,14 @@ describe("ChainTableBody — chain rows (chips + connectors)", () => {
 		// owner ruling: the derivation is already encoded in the chain line —
 		// no conclusion marker down here
 		assert.ok(!html.includes("prop-conclusion"), "no conclusion marker anywhere");
-		// statements indent DEEPEST (pl-[4.75rem]); chains pl-11 under clusters
-		assert.ok(html.includes("pl-[4.75rem]"), "the deepest indent");
-		assert.ok(html.includes("pl-11"), "the chain indent");
+		// THE ALIGNMENT STAIRCASE (owner ruling, round 3): each level's
+		// checkbox sits under its parent's expander arrow. The expander
+		// shares the checkbox's 14px width, so each step is 18px: clusters
+		// pl-3 (12) → chains pl-7.5 (30 = the cluster expander) →
+		// statements pl-12 (48 = the chain expander)
+		assert.ok(html.includes("pl-12"), "statements under the chain's expander");
+		assert.ok(html.includes("pl-7.5"), "chains under the cluster's expander");
+		assert.ok(html.includes("h-5 w-3.5"), "the expander shares the checkbox's 14px width");
 	});
 });