Warm typediagram renderer during VS Code activation for markdown preview

[abdushakoor12]

TLDR

Warm the VS Code typeDiagram sync renderer during extension activation so the first Markdown preview render produces SVG instead of leaving a pending raw-code placeholder. Fixes #21.

Details

What Was Added:

• A cold-start regression test in packages/vscode/test/extension.test.ts that mocks a not-yet-warm typediagram-core, activates the extension, renders a typeDiagram Markdown fence, and asserts the first render contains SVG and not typediagram-pending.

What Was Changed/Deleted:

• packages/vscode/src/extension.ts now makes activate async and awaits warmupSyncRender() before returning the extendMarkdownIt contribution when the sync renderer is still cold.
• The activate-time warmup path logs success and failure explicitly.
• packages/vscode/test/extension.test.ts now awaits activate(...) throughout the extension-host tests to match the async activation contract.
• The existing markdown preview refresh test now explicitly mocks a cold renderer so it remains deterministic after activate-time warmup.

Spec/Doc Changes:

• None.

Breaking Changes:

• No.

How Do The Automated Tests Prove It Works?

• make ci passed.
• packages/vscode/test/extension.test.ts includes [VSCODE-MD-COLD-FIRST-RENDER] waits for warmup before exposing markdown preview so the first render is SVG, which directly covers the reported failure mode.
• packages/vscode/test/extension.test.ts also still verifies [VSCODE-MD-EXTEND] extendMarkdownIt schedules a preview refresh after warmup, proving the cold-path refresh behavior remains wired.
• The full packages/vscode suite passed with 132 passed, 1 skipped, and the full workspace CI run completed successfully.