fix(workspace): single scroll area, drag cleanup, thin note titles with bundled Inter

- the workspace fills the window; only the note scrolls (also on phones, where the
  sideways scroll area used to scroll on its own)
- clear drag state on dragend, calmer sidebar toggle when collapsed
- ship Inter as variable font, light and larger note titles; header shows the
  title only after the big title scrolled away and stays one row on phones
- main builds show the package version without -dev

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

frontend/package-lock.json

@@ -9,6 +9,7 @@
       "version": "0.9.0",
       "license": "Unlicense",
       "dependencies": {
+        "@fontsource-variable/inter": "5.3.0",
         "@types/prismjs": "^1.26.6",
         "emoji-picker-react": "4.12.0",
         "framer-motion": "^11.15.0",
@@ -1024,6 +1025,15 @@
         "node": "^18.18.0 || ^20.9.0 || >=21.1.0"
       }
     },
+    "node_modules/@fontsource-variable/inter": {
+      "version": "5.3.0",
+      "resolved": "https://registry.npmjs.org/@fontsource-variable/inter/-/inter-5.3.0.tgz",
+      "integrity": "sha512-OupL48va4JNofb97w6NYeF9S7W/kHNKM0Er8Dem5nqi4jeOLrVJDoE8tZEpnMJmtkvNbB1EIPPwHcdkF6b1oUA==",
+      "license": "OFL-1.1",
+      "funding": {
+        "url": "https://github.com/sponsors/ayuhito"
+      }
+    },
     "node_modules/@humanfs/core": {
       "version": "0.19.2",
       "resolved": "https://registry.npmjs.org/@humanfs/core/-/core-0.19.2.tgz",