Resolves structural divergence introduced by PR #129 (squashed into ccdac51 on main). The 3f60897 sync commit pre-merged only the --scale flag removal, CommonOptions field reorder, and 3D bevel/line cosmetic tweaks. The deeper refactors from #129 (LinearDefaults, ChartSelection, ParseChartSpecs, DatasetSettings{Charts,Axes,ChartSettings,Sort,Scale,ShowLabels}) are superseded by settings-architecture's per-chart Config registry (config/charts/{bar,line,pie,heatmap,radar}/Materialise).

All 20 unmerged files resolved in favour of the new architecture per design spec docs/superpowers/specs/2026-06-16-settings-architecture-design.md:

  cmd/charts/{bar,heatmap,line,pie,radar}/{name,_test}.go  (10 files)
  cmd/cli/{options_test,pipeline,pipeline_test}.go         (3 files)
  cmd/{root,root_test,ui,ui_test}.go                       (4 files)
  pkg/template/vizb-ui.gen.go                              (1 file)
  shared/{chart_spec,chart_spec_test}.go                   (2 files)

Audit: test counts match 1:1 across branches; the two architectures are mutually exclusive at the type/function signature level, so no test cases from main port over. go build ./... and go test -count=1 ./... pass.

…stry panel (#130)

- **Wire format**: `Dataset.Settings` is now `[]config_charts.ChartConfig` (typed per-chart: bar/line/pie/heatmap/radar). v0.12.0 files are auto-migrated in-memory on read via `shared.MigrateDataset`. See CHANGELOG 0.13.0.
- **Per-chart config registry** (`config/charts/`): `ChartConfig` interface + `Register`/`New`/`Decode`/`Registered`/`Factory`. Each chart subdir (`bar`, `line`, …) self-registers via `init()`. `Materialise(flags, *Config)` is the typed build entry point.
- **CLI refactor**: replaces `shared.FlagState` with `cli.CommonOptions` → `LinearOptions` → per-chart options; `vizb bar|line|pie|heatmap|radar` subcommands self-register via `init()`. The per-chart subcommand `Run` calls `Materialise` and passes the typed `*Config` to a new `cli.RunSingleChart(cmd, args, common, configs)`. `assembleDataset` / `applySelections` now set `dataSet.Settings = configs` directly. Re-introduces the `cli.ValidateScale` call that the previous per-chart-subcommand refactor had dropped.
- **UI panel**: schema-less `SettingsPanel` walks a `fieldRegistry` (`appliesTo: ChartType[]` + `appliesOn: Dimension[]` per field) and renders the registered control for each known key. Adding a field is one registry entry + one Vue file; new chart types ride along automatically. `autoRotate` declares `appliesOn: ['3D']` and is hidden for 2D data.
- **Chart-type picker** auto-switches from a tabs row to an icon+name combobox when the active dataset exposes more than 3 chart types (constant `CHART_PICKER_TAB_THRESHOLD = 3`).
- **Bug fixes**: `setScale`/`setAutoRotate` no longer silently no-op on freshly migrated configs (the `'X' in cfg` guard was removed); `useDataPoint` keeps settings reactive by only `markRaw`-ing the rows (the data field), not the whole DataSet; the swap handler now calls `useDataPoint.setArrangement` + group/color reset (matching the old `AxisSwapper` behavior).
- **Sample data**: `ui/src/data/sample.json` migrated to the new `ChartConfig[]` shape; all 6 datasets preserved, including the Worker Pool Benchmarks "no charts" entry.
- **Dead code removed**: `AxisSwapper.vue`, `ChartSettings.vue`, `AutoRotateToggle.vue`, `ScaleSelector.vue`, `shared/chart_config.go`, `cmd/flag_validation_rules.go`, `LinearDefaults`/`applyDefaults`/`selectionSettings`/`ChartSelection`/`SelectionsFromCharts`, the `axisKeyConcat` helper, and the v0.12.0 `DatasetSettings`/`ChartSettings`/`Defaults` structs.
- **Sync with main (#129)**: removes `--scale` from root and syncs the 3D bar/line bevel/width values that were squashed into #129.