Docs: park border-identity question and UX follow-ups for batched council

docs/ux-second-pass.md

@@ -8,6 +8,57 @@ record the resolution into the contract (`docs/architecture/09`+`10` and the rel
 
 ## Open
 
+- **Border weight as identity — boxed fields vs Carbon's quieter defaults**
+  (**priority: pick this up first, next session** — user-flagged 2026-06-12).
+  Carbon's own defaults use far fewer boxes than we do: fields are filled with a
+  bottom border only (`reference/carbon` → text-input `_text-input.scss`,
+  `border-block-end` only), secondary buttons are a gray _fill_, tertiary is the
+  only outlined button (`_button.scss` → `button-theme(transparent,
+$button-tertiary, …)`), and tiles separate by layer steps with full borders
+  only behind an accessibility feature flag. Our fully-boxed fields/secondaries
+  are a recorded divergence (arch 09 §2 + §4) and the box-discipline rules now
+  contain the noise — the open question is whether to go further toward Carbon
+  (bottom-border-only fields, filled secondary) or keep the boxed look as
+  deliberate identity. An identity decision, not cleanup: it would repaint every
+  field in the app. Council seats: Carbon (canon above), NN/g (affordance of
+  boxed vs underlined inputs), a11y (3:1 non-text contrast for field boundaries
+  either way).
+
+- **Two visible "Export" buttons** (`App.tsx` header — workspace export;
+  `ChartExport.tsx` in the preview header — per-chart export). Same label,
+  different scope, both visible at once. Candidate fix: rename one ("Export
+  chart" / "Export workspace") or differentiate via grouping.
+
+- **"LATER" facet placeholders in Chart Builder shelves**
+  (`ChartBuilderModal.module.css` → `.facetSlot`/`.facetTag`). Internal roadmap
+  language shipped to users. Either hide the affordance until faceting works or
+  write user-facing copy.
+
+- **Default snippet names are timestamps** ("Snippet 2026-06-10 18:04:37") — the
+  library reads like a downloads folder next to builder-generated names ("Bar
+  chart of count by Ship Mode"). Candidate: derive a content-based name from the
+  spec (mark + encoded fields) when the user never renames.
+
+- **Fit-mode tab labels** ("Original / Width / Height / Full", `LivePreview.tsx`)
+  are terse for a first-time user; tooltips likely suffice.
+
+- **Donate is the most saturated element on screen** (header soft-accent wash) —
+  visually outranks Publish/Build Chart. Decide whether intentional.
+
+- **Left rail affordance** (`PaneToggleStrip.tsx`): three unlabeled glyphs + a
+  tall empty strip; pane toggles aren't discoverable without hovering.
+
+- **Pane toggle pressed state = hover state** (`PaneToggleStrip.module.css`).
+  The pressed chip is a `--layer-02` fill — the same fill the strip's IconButtons
+  use on hover — so hovering an off toggle looks identical to an on toggle at
+  rest. (The pressed chip's `--border-strong` border used to disambiguate; it was
+  dropped in the box-discipline pass.) Candidate cues: a filled/accent glyph,
+  an inset edge marker, or restoring a border for the on state only.
+
+- **Dataset detail schema density** (`DatasetsModal.tsx`): one field per row
+  makes a 25-column dataset a long scroll before the preview table; a denser
+  two-column field list would fit overview + schema + preview on one screen.
+
 - **Chart theme picker placement & header crowding** (`LivePreview.tsx` — ChartThemeControl).
   The picker sits in the preview header because nesting a SelectControl inside the
   PreviewSettings popover is impossible today (one-open-popover registry: the select would