Release v0.4.0

[schloerke]

Summary

Cuts shinychat 0.4.0 (date: 2026-05-21) since 0.3.1:

• feat: support images and PDFs in tool results #225 (New features) — tool result cards render images and PDFs from chatlas content items.
• feat: add stream cancellation support #221 (New features) — enable_cancel param + stop button wired to chatlas.StreamController.
• feat: auto-promote suggestion lists to clickable card grid #219 (New features) — suggestion-list spans rendered as a clickable suggestion-card grid.
• feat: add thinking/reasoning display UI #208 (New features + Improvements) — thinking-content panels; chatlas>=0.15.0 floor.
• fix: align custom .tagify() annotations with htmltools Tagified contract #226 (Bug fixes) — htmltools 0.7.0 / Tagifiable-contract compat for split_html_islands and the Tool*Component.tagify() implementations.
• feat(mod): Add set_client() and status to chat_mod_server() return value #227 (New features) — adds set_client() and status to chat_mod_server() return value

Minor-version bump (0.3.x → 0.4.0) reflects the new user-facing features.

Commits

• Release v0.3.2 — renames ## [0.3.2] - Unreleased → ## [0.3.2] - 2026-05-21 and adds the ### Bug fixes subsection for fix: align custom .tagify() annotations with htmltools Tagified contract #226.
• chore(py): bump release to v0.4.0 and reorder changelog sections — bumps the heading to [0.4.0] - 2026-05-21 and reorders subsections to New features → Improvements → Bug fixes.

After merge

1. Tag the merge commit v0.4.0.
2. Publish a GitHub Release on that tag.
3. The release workflow handles uv build + trusted PyPI publish.

hatch-vcs derives the version from the tag.