Onboarding: paste-a-spec door, workspace-import and learn links

docs/spec/02-snippet-library.md

@@ -24,7 +24,9 @@ When the library is empty — on first run, or after the user deletes their last
 - The canvas briefly identifies what Astrolabe is, then offers the ways to begin.
 - **Create your first snippet** — the primary action; starts a new snippet from the sample bar-chart template and opens it in the editor (identical to _Create New_ under _Snippet Operations_).
 - **Build a chart from your data** — the data-first door beside the primary; opens the **Chart Builder** over the canvas. With no datasets yet, the builder's no-datasets state explains itself and leads to "Add a dataset" (see _Chart Builder → Opening_) — the path never dead-ends. Opening the builder also lays the workspace out at the default split below, since creating from the builder leaves the canvas directly.
-- An **example gallery** of a few simple snippets showcasing distinct Vega-Lite capabilities (e.g. a bar chart, a time-series line, a scatter plot, a stacked area, a donut, a binned histogram). Each example shows a **live preview** of the chart and a one-line description.
+- **Paste a spec you already have** — the bring-your-own door for users arriving with existing Vega-Lite JSON (a notebook, the Vega editor, an AI chat). A disclosure button (not a modal) reveals a labelled paste area in place; **Add to library** creates the snippet from the pasted text and opens it in the editor, **Cancel** collapses the panel and returns focus to the button. The panel stays mounted while collapsed, so a draft paste survives. Pasted text is accepted as-is — the editor's live validation is where an almost-right spec gets fixed — and the snippet's name derives from the spec (its `title`, else a "Mark chart of y by x" phrase), falling back to "Pasted spec".
+- Below the doors, two quiet secondary links: **Import your workspace** (for users restoring a workspace export — same file-picker import as the header control, see _Import & Export_) and **Read the deep dives** (the `/learn/` section, opened in a new tab).
+- An **example gallery** of a few simple snippets showcasing distinct Vega-Lite capabilities (e.g. a bar chart, a time-series line, a scatter plot, an interactive brushed scatter, a stacked area, a donut, a binned histogram). Each example shows a **live preview** of the chart and a one-line description.
   - **Add** on an example creates it as an ordinary snippet and makes it active (opening it in the editor).
   - **Add all** creates the whole set at once and makes one of them active.
 - Added examples are **ordinary snippets**: meaningfully named (not auto-generated timestamps), and thereafter editable, duplicable, and deletable like any other — they are the user's, not a special class (_own your data_).