Expose shared inventory UI for LabSTRA

[lhparker1]

What changed

• exports host-neutral ASTRA record, output, decision, paper, and inventory detail components
• adds host-provided PDF.js asset routing for JupyterLab
• builds the shared theme-astra and store-types workspaces as consumable packages
• adds coverage for shared record-detail behavior

Why

LabSTRA needs the same ASTRA inventory and provenance presentation used by MySTRA without depending on an uncommitted sibling checkout or on the MySTRA application runtime.

Impact

This creates a commit-pinnable compatibility surface for the JupyterLab prototype while keeping the publication-theme changes outside this PR.

Checks

• npm run typecheck -w @astra-spec/theme-astra
• npm run build -w @astra-spec/store-types
• npm run build -w @astra-spec/theme-astra
• 11 targeted Vitest tests across inventory outputs and record details

[lhparker1]

Closing as superseded by #7 and the viewer/Jupyter split. Shared project inspection components now live in astra-viewer and are consumed by jupyterlab-astra; astra-theme remains paper-only.