fix(build): transpile watcher stages codicon.ttf so dev-mode icons render

[Pterjudin]

Summary

codicon.ttf ships in node_modules/@vscode/codicons/dist/ and is normally moved into src/vs/base/browser/ui/codicons/codicon/ by gulp's copy-codicons task before transpile runs. The font file is .gitignore'd (correctly — it's a build artifact).

The watch-client-transpile entry point (build/next/index.ts) doesn't depend on gulp. So a dev who runs only:

npm run watch-client-transpile
./scripts/code.sh

(instead of the full npm run watch, which fans out to both) ends up with:

• no font in src/
• no font in out/ (because copyAllNonTsFiles globs src/**/*)
• every workbench glyph rendering as a tofu box (□)

I hit this myself running the dev IDE this afternoon — the symptom is unambiguous and a fresh contributor would lose at least 20 minutes chasing it through Chromium's font-query logs before finding the gulp task.

Fix

One idempotent helper ensureCodiconFontStaged() called from the top of copyAllNonTsFiles():

• destination exists → no-op (the common case after first build)
• node_modules source missing → warn and continue (don't break the build over an icon)
• otherwise → copy once, log it

Cost per build cycle: one fs.existsSync() call.

1 file changed, +21 / -0.

Test plan

• Hygiene passes (was the second commit attempt; brace-style violation fixed)
• rm -rf src/vs/base/browser/ui/codicons/codicon/codicon.ttf && npm run watch-client-transpile — confirm [codicons] Staged codicon.ttf into … appears on the next build cycle
• ./scripts/code.sh after the above — confirm workbench icons render correctly
• Re-run the watcher with the font already staged — confirm no log line and the build still succeeds (idempotent path)

🤖 Generated with Claude Code