chore: add prettier with format scripts

Prettier config (no semi, single quotes, 100 cols, tailwindcss plugin)
scoped via .prettierignore to frontend code only; markdown, docs, CI
workflows, website/, and src-tauri/ are excluded. Scripts follow the
toolchain split: format/format:check (prettier), format:rust(:check)
(cargo fmt), format:all for both.

pnpm-lock.yaml

@@ -72,6 +72,12 @@ importers:
       '@vitejs/plugin-react':
         specifier: ^4.6.0
         version: 4.7.0(vite@7.3.1(@types/node@26.0.1)(jiti@2.6.1)(lightningcss@1.32.0))
+      prettier:
+        specifier: ^3.9.4
+        version: 3.9.4
+      prettier-plugin-tailwindcss:
+        specifier: ^0.8.0
+        version: 0.8.0(prettier@3.9.4)
       tailwindcss:
         specifier: ^4.2.2
         version: 4.2.2
@@ -1180,6 +1186,66 @@ packages:
     resolution: {integrity: sha512-OW/rX8O/jXnm82Ey1k44pObPtdblfiuWnrd8X7GJ7emImCOstunGbXUpp7HdBrFQX6rJzn3sPT397Wp5aCwCHg==}
     engines: {node: ^10 || ^12 || >=14}
 
+  prettier-plugin-tailwindcss@0.8.0:
+    resolution: {integrity: sha512-V8ITGH87yuBDF6JpEZTOVlUz/saAwqb8f3HRgUj8Lh+tGCcrmorhsLpYqzygwFwK0PE2Ib6Mv3M7T/uE2tZV1g==}
+    engines: {node: '>=20.19'}
+    peerDependencies:
+      '@ianvs/prettier-plugin-sort-imports': '*'
+      '@prettier/plugin-hermes': '*'
+      '@prettier/plugin-oxc': '*'
+      '@prettier/plugin-pug': '*'
+      '@shopify/prettier-plugin-liquid': '*'
+      '@trivago/prettier-plugin-sort-imports': '*'
+      '@zackad/prettier-plugin-twig': '*'
+      prettier: ^3.0
+      prettier-plugin-astro: '*'
+      prettier-plugin-css-order: '*'
+      prettier-plugin-jsdoc: '*'
+      prettier-plugin-marko: '*'
+      prettier-plugin-multiline-arrays: '*'
+      prettier-plugin-organize-attributes: '*'
+      prettier-plugin-organize-imports: '*'
+      prettier-plugin-sort-imports: '*'
+      prettier-plugin-svelte: '*'
+    peerDependenciesMeta:
+      '@ianvs/prettier-plugin-sort-imports':
+        optional: true
+      '@prettier/plugin-hermes':
+        optional: true
+      '@prettier/plugin-oxc':
+        optional: true
+      '@prettier/plugin-pug':
+        optional: true
+      '@shopify/prettier-plugin-liquid':
+        optional: true
+      '@trivago/prettier-plugin-sort-imports':
+        optional: true
+      '@zackad/prettier-plugin-twig':
+        optional: true
+      prettier-plugin-astro:
+        optional: true
+      prettier-plugin-css-order:
+        optional: true
+      prettier-plugin-jsdoc:
+        optional: true
+      prettier-plugin-marko:
+        optional: true
+      prettier-plugin-multiline-arrays:
+        optional: true
+      prettier-plugin-organize-attributes:
+        optional: true
+      prettier-plugin-organize-imports:
+        optional: true
+      prettier-plugin-sort-imports:
+        optional: true
+      prettier-plugin-svelte:
+        optional: true
+
+  prettier@3.9.4:
+    resolution: {integrity: sha512-yWG/o/4oJfo036EKAfK6ACAoDOfHeRHx4tuxkfBZiauURiaSmYwlpOr5LQqKtIkRD2z1PLteme2WoxEnj4tHTg==}
+    engines: {node: '>=14'}
+    hasBin: true
+
   react-dom@19.2.4:
     resolution: {integrity: sha512-AXJdLo8kgMbimY95O2aKQqsz2iWi9jMgKJhRBAxECE4IFxfcazB2LmzloIoibJI3C12IlY20+KFaLv+71bUJeQ==}
     peerDependencies:
@@ -2110,6 +2176,12 @@ snapshots:
       picocolors: 1.1.1
       source-map-js: 1.2.1
 
+  prettier-plugin-tailwindcss@0.8.0(prettier@3.9.4):
+    dependencies:
+      prettier: 3.9.4
+
+  prettier@3.9.4: {}
+
   react-dom@19.2.4(react@19.2.4):
     dependencies:
       react: 19.2.4