Slice 3 setup: Tailwind v4 + DaisyUI v5 (dracula enabled) + 'tab' vocab

- add tailwindcss@4 + @tailwindcss/vite + daisyui@5; vite tailwind plugin
- src/app.css: @import tailwindcss + @plugin daisyui { themes: dracula --default }
  (theme BUNDLED, not just named); imported in main.ts
- index.html: <html data-theme="dracula">
- biome.json: enable css tailwindDirectives so @plugin parses
- GLOSSARY: define FE term 'tab' (workspace slot referencing a conversation;
  holds conversationId + model + title; close = local forget)

Verified: dracula tokens bundled in CSS, svelte-check 0/0, vitest 222, biome
clean, build ok.

1 files changed, 1 insertions, 1 deletions

diff --git a/index.html b/index.html
index 32b56aa..117e502 100644
--- a/index.html
+++ b/index.html
@@ -1,5 +1,5 @@
 <!doctype html>
-<html lang="en">
+<html lang="en" data-theme="dracula">
 	<head>
 		<meta charset="UTF-8" />
 		<meta name="viewport" content="width=device-width, initial-scale=1.0" />