Add two new root `type:`s on the shared layered engine:

- `flowchart` — process/decision graphs (process cards, decision diamonds,
  I/O parallelograms, start/end terminators) joined by labelled `links:`,
  with `"[*]"` start/end pseudo-steps.
- `mindmap` — radial topic trees with items and body copy.

Both ship a model builder and a fluent authoring builder, and reuse the
existing measure/route/svg/animate stages. Shared engine work supports both:
diamond/parallelogram shapes and loop-back routing (EdgePainter,
OrthogonalRouter, SvgRenderer, CardSizer), plus token/schema/enum plumbing.

Includes guide + reference docs, playground examples for mindmap, corpus
diagrams, and model/SVG goldens; clean-line fuzzer coverage extended to the
new shapes. Full suite green (505 tests).

Add a Flowchart group to the docs playground's Examples picker:

- Two example diagrams — "Deploy gate" (TB, decisions + rollback loop) and
  "Ticket triage" (LR, routed by urgency) — under wwwroot/examples.
- Register the group in PlaygroundIsland's ExampleGroups (glyph, pill tag).
- Teal `data-type="flowchart"` pill colour (light + dark) in BrandStyling.

Also add the repo's first Claude skill, add-playground-example, documenting
the three-file process (author YAML, register in the picker, add the pill
colour) so future playground additions are mechanical.

Add a chart root `type:` that renders a small, static data chart on its own
painter, bypassing the node/edge layout+route+animate pipeline. Charts share
the meta/theming shell with every other diagram but carry no nodes, edges, or
flow.

- Model: ChartModel/ChartSeries/ChartPoint schema + ChartBuilder parser, wired
  through DiagramType.Chart, Tokens, Defaults, and Validate. Which series member
  carries data depends on kind (bar/pie/donut → one magnitude, line → a value
  list, scatter → x/y points).
- Svg: ChartPainter draws bar/line/pie/donut/scatter plus an optional legend
  (top/right/bottom/none, optional value annotations) and pie/donut centre
  labels; non-finite data collapses to 0 so no bad coordinate reaches the SVG.
  ChartColors derives every series colour from `--beck-primary` via the chosen
  palette (analogous/monochromatic/complementary/sequential) as
  color-mix/relative-colour expressions, so a chart re-tints with the host
  palette and flips light↔dark like the rest of Beck. A series may pin its own
  `color:`.
- Authoring: ChartDiagramBuilder fluent API + ChartKind/ChartPalette/
  LegendPlacement enums and their `Tokens.Of` mappings.
- Docs: chart guide, yaml reference, for-ai.llms.md; five wwwroot examples and
  four guide snippets; playground picker entry + pill colour.
- Tests: ChartTests and ChartQuality clean-line coverage. Full suite green
  (533 tests).

Also gitignore `*.snupkg` and `/dist/` local pack output, and add oracle
renders for the flowchart/mindmap types.