The board's symbol takes a tint — a 4×2 colour row under the picker's glyphs, and the glyph itself moves into the titlebar

iconColor stops being hand-written-only (user-ruled, superseding 03's
"schema yes, control no"): it rides StyleCommand.apply → applyStyle as
the third styled dimension — per-dimension no-op skip, one bracket, one
history step, ExpectedField.iconColor for staleness. The SymbolPicker
grows an opt-in colour row (leading None plus seven Palette.foregrounds
hues, None removes the key); the board popover is its one caller. The
window-title widget now draws the board's resolved glyph in that tint
beside the name. Doc realignment filed on the Redesign board (Minor).

Claude-Session: https://claude.ai/code/session_01SR4XGjmBE16ZUYWpfFHXwY

KanbanTests/StyleWriteTests.swift

@@ -33,7 +33,8 @@ private func styled(order: String, title: String, keys: [String] = []) -> String
 }
 
 /// The board root's own `index.md` — styled like any other item (`StyleTarget.board`), and carrying
-/// an `iconColor` the app must never touch (schema yes, control no).
+/// an `iconColor` a gesture that never names that dimension must leave alone (it stopped being
+/// hand-written-only when the board popover's symbol picker grew its colour row, 2026-08-07).
 private let boardIndex = """
 ---
 schema: 1
@@ -143,13 +144,38 @@ struct StyleWriteTests {
         let after = try fixture.indexText("\(Ident.lane1)/\(Ident.card1)")
         #expect(after.contains("background: {color: \"dark-teal\"}"))
         #expect(after.contains("icon: flag"))
-        // "iconColor: resolved — schema yes, control no" (03 § Styling ▸ Capabilities): the field
-        // renders when hand-written and the app offers no control for it, so a style write must
-        // carry it through untouched like any unknown key.
+        // The third dimension is a control now (the symbol picker's colour row), but a gesture
+        // that never names it must still carry it through untouched — per-dimension `.keep`.
         #expect(after.contains("iconColor: chalk"))
         #expect(!after.contains("fern"), "the old value is replaced, not duplicated")
     }
 
+    @Test("The colour row's dimension: iconColor sets as a plain scalar, removes as an absent key, and no-ops in place")
+    func iconColorIsTheThirdDimension() throws {
+        let fixture = try makeBoard()
+        defer { fixture.tearDown() }
+        let store = try BoardStore(rootURL: fixture.root)
+        let log = BracketLog()
+        log.attach(to: store)
+
+        // The fixture's board already carries `iconColor: carnation` — re-choosing it is a no-op
+        // against the loaded snapshot, `skipsNoOps`'s rule at the third dimension.
+        store.applyStyle(to: .board, iconColor: .set("carnation"))
+        #expect(log.begins == 0, "re-choosing the tint an item already carries opens no bracket")
+
+        store.applyStyle(to: .board, iconColor: .set("fern"))
+        let set = try fixture.indexText("")
+        #expect(set.contains("iconColor: fern"))
+        #expect(!set.contains("carnation"), "the old tint is replaced, not duplicated")
+        #expect(!set.contains("icon: "), "the untouched icon dimension writes no key of its own")
+
+        store.applyStyle(to: .board, iconColor: .remove)
+        let removed = try fixture.indexText("")
+        #expect(!removed.contains("iconColor"))
+        #expect(!removed.contains("\"\""), "a removal is a missing key, never an empty string")
+        #expect(store.banners.oneShots.isEmpty)
+    }
+
     @Test("The None and default wells remove their key rather than writing a blank value")
     func removesTheKey() throws {
         let fixture = try makeBoard()