Fork Notesium source and restructure into Go package layout

Initial fork of github.com/alonswartz/notesium into librenotes:
- Source moved to internal/notesium/ (package notesium)
- Thin entry point at cmd/librenotes/main.go
- Module renamed to git.librete.ch/public/librenotes
- main() exposed as notesium.Run()
- LICENSE preserved (MIT), NOTICE added with attribution
- Web assets and completion.bash co-located with embedding code
  to satisfy go:embed path constraints

Closes #3, #34, #35.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

internal/notesium/web/app/empty.js

@@ -0,0 +1,60 @@
+var t = `
+<div class="mx-auto w-96">
+  <h3 class="mt-40 font-medium text-gray-400 text-xl mx-auto text-center">notesium</h3>
+  <div class="mt-10">
+    <template v-for="entry in entries">
+      <div class="flex items-center justify-between p-4 text-sm font-medium cursor-pointer hover:bg-gray-100 rounded-xl"
+        @click="$emit(entry.emit[0], entry.emit[1])">
+        <div class="flex items-center space-x-4 text-gray-500">
+          <Icon :name="entry.icon" size="h-4 w-4" />
+          <span v-text="entry.title"></span>
+        </div>
+        <span class="whitespace-nowrap text-gray-900 font-mono mt-1" v-text="entry.keybind"></span>
+      </div>
+    </template>
+  </div>
+</div>
+`
+
+import Icon from './icon.js'
+export default {
+  components: { Icon },
+  emits: ['note-new', 'note-daily', 'finder-open'],
+  data() {
+    return {
+      entries: [
+        {
+          title: 'New note',
+          keybind: 'space n n',
+          icon: 'outline-plus',
+          emit: ['note-new'],
+        },
+        {
+          title: 'Daily note',
+          keybind: 'space n d',
+          icon: 'outline-calendar',
+          emit: ['note-daily'],
+        },
+        {
+          title: 'List notes',
+          keybind: 'space n l',
+          icon: 'mini-bars-three-bottom-left',
+          emit: ['finder-open', '/api/raw/list?color=true&prefix=label&sort=alpha'],
+        },
+        {
+          title: 'Search notes',
+          keybind: 'space n s',
+          icon: 'mini-magnifying-glass',
+          emit: ['finder-open', '/api/raw/lines?color=true&prefix=title'],
+        },
+        {
+          title: 'Graph view',
+          keybind: 'space n g',
+          icon: 'graph',
+          emit: ['graph-open'],
+        },
+      ],
+    }
+  },
+  template: t
+}