More efficient flat file list format and various UX improvements (#3)

This is a major upgrade with assorted things included.

- Navigation flows improved, search appears in URL history, cleared when navigating to another folder
- More efficient file list format for faster loads
- Efficient updates, never re-send full root another time (except at connection)
- Large number of watching and filelist updates (inotify issues remain)
- File size coloring
- Fixed ZIP generation random glitches (thread race condition)
- Code refactoring, cleanup, typing fixes
- More tests

Reviewed-on: #3

frontend/tsconfig.node.json

@@ -0,0 +1,16 @@
+{
+  "extends": "@tsconfig/node18/tsconfig.json",
+  "include": [
+    "vite.config.*",
+    "vitest.config.*",
+    "cypress.config.*",
+    "nightwatch.conf.*",
+    "playwright.config.*"
+  ],
+  "compilerOptions": {
+    "composite": true,
+    "module": "ESNext",
+    "moduleResolution": "Bundler",
+    "types": ["node"]
+  }
+}