fix(desktop): render codicons when running hgui from a worktree

[OutThisLife]

Summary

Codicons (and the @nous-research/ui Collapse font) silently fail to render whenever the desktop app is launched via hgui from a git worktree — the glyphs just disappear.

Root cause: hgui symlinks the worktree's node_modules back to the main checkout. Vite calls realpath before enforcing server.fs.allow, so requests like @vscode/codicons/dist/codicon.ttf resolve to …/hermes-agent/node_modules/… — outside the worktree root — and get rejected:

The request id ".../node_modules/@vscode/codicons/dist/codicon.ttf" is outside of Vite serving allow list.

Fix: whitelist the real node_modules locations in server.fs.allow, resolving symlinks via realpathSync. Works from any worktree and is a no-op in the main checkout.

Test plan

• hgui <worktree> → codicons + Collapse font render, no outside of Vite serving allow list warnings
• hgui from the main checkout still works unchanged

[OutThisLife]

The server.fs.allow fix (realpath-resolved node_modules whitelist) already landed on main independently, so there's nothing left to merge from this branch — the rest of its diff is just staleness. Folded into the combined desktop dev-experience PR #69938. Closing as implemented on main.