Bump version to 0.8.0 (Phase 8 milestone)

[vicmaster]

Summary

Closes Phase 8 — Renderer expressiveness. Bumps package.json and the MCP server name from 0.7.0 to 0.8.0.

Phase 8 shipped in five PRs

• Phase 8 #1: auto position:relative on orphan absolute descendants #31 — auto position: relative injection (foot-gun fix)
• Phase 8 #2: custom font loading via @font-face #32 — custom font loading (set_fonts / get_fonts, @font-face emission, preconnect)
• Phase 8 #3: composable backdrop-filter (blur + saturate + brightness + contrast) #33 — composable backdropFilter (blur / saturate / brightness / contrast)
• Phase 8 #4: 'path' node type for custom SVG paths #34 — path node type (custom SVG paths beyond Lucide)
• Phase 8 #5 (final): animations + structured transitions #35 — animations + structured transitions (built-in keyframes library)

Plus #36 (style attribute escape fix found while dogfooding) and #37 (Phase 8 release page hero composed via canvas-mcp itself).

Test plan

After merge:

• Tag v0.8.0 on master
• Create GitHub release with notes + docs/phase8-release.png as hero