board: a tag in the prose is coloured where it sits, not printed twice

A tagged note was showing its tag twice — once where it was typed, once as a
chip — and the duplicate was the loud copy. Now the chip row carries only what
the body cannot say (a tag lifted off its own line, a label from the picker),
and a `#tag` left mid-sentence is tinted in place.

Which characters are a tag is asked of the CORE, the way the card already asks
it which lines are checklist items: `extract_tag_spans` keeps the spans
`extract_tags` throws away, and `body_tags` hands them to Kotlin. Offsets are
UTF-16 code units, because `AnnotatedString` and JS both index that way and a
char index lands mid-token the first time somebody writes an emoji. The web
keeps its own matcher in markdown.ts, mirroring `line_tags` case for case.

The inline ink is its own table, one Tailwind step deeper than the chip's. A
chip brings its own -100 fill and reads against that alone; inline text sits on
whatever the card is, including a gray-tagged card at neutral-200 — where the
chip's -700 measured 3.98 (green), 4.11 (orange) and 4.34 (teal), under the 4.5
body text needs. At -800/-300 every hue lands 5.63-12.01 light and 7.20-10.84
dark across every palette and generated fill.

Chips now carry the `#` on every surface. The via_tag branch that used to
decide it is gone from the card, and Android's row said no hash at all.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>

frontend/src/components/MarkdownText.vue

@@ -3,7 +3,13 @@ import { computed } from "vue";
 import { parseMarkdown } from "../notes/markdown";
 import MarkdownInline from "./MarkdownInline.vue";
 
-const props = defineProps<{ text: string; toggleable?: boolean }>();
+// `tagColors` is passed straight through to MarkdownInline — see there for why the
+// card owns the lookup rather than the renderer.
+const props = defineProps<{
+  text: string;
+  toggleable?: boolean;
+  tagColors?: Record<string, string>;
+}>();
 // Ticking a box rewrites a line of the note's body, which is a thing only the owner
 // of that note can do — so this renders the checkbox and hands the intent up rather
 // than reaching for the store itself. The card wires it; a read-only render does not
@@ -15,14 +21,20 @@ const blocks = computed(() => parseMarkdown(props.text));
 <template>
   <div class="space-y-1.5 break-words">
     <template v-for="(b, i) in blocks" :key="i">
-      <h3 v-if="b.type === 'h1'" class="text-base font-bold"><MarkdownInline :tokens="b.inline ?? []" /></h3>
-      <h4 v-else-if="b.type === 'h2'" class="text-sm font-bold"><MarkdownInline :tokens="b.inline ?? []" /></h4>
-      <h5 v-else-if="b.type === 'h3'" class="text-sm font-semibold"><MarkdownInline :tokens="b.inline ?? []" /></h5>
+      <h3 v-if="b.type === 'h1'" class="text-base font-bold">
+        <MarkdownInline :tokens="b.inline ?? []" :tag-colors="tagColors" />
+      </h3>
+      <h4 v-else-if="b.type === 'h2'" class="text-sm font-bold">
+        <MarkdownInline :tokens="b.inline ?? []" :tag-colors="tagColors" />
+      </h4>
+      <h5 v-else-if="b.type === 'h3'" class="text-sm font-semibold">
+        <MarkdownInline :tokens="b.inline ?? []" :tag-colors="tagColors" />
+      </h5>
       <blockquote
         v-else-if="b.type === 'quote'"
         class="whitespace-pre-wrap border-l-2 border-neutral-300 pl-2 text-neutral-600 dark:border-neutral-600 dark:text-neutral-400"
       >
-        <MarkdownInline :tokens="b.inline ?? []" />
+        <MarkdownInline :tokens="b.inline ?? []" :tag-colors="tagColors" />
       </blockquote>
       <div v-else-if="b.type === 'task'" class="flex flex-col gap-1">
         <div v-for="(it, j) in b.items ?? []" :key="j" class="flex items-start gap-2">
@@ -42,22 +54,22 @@ const blocks = computed(() => parseMarkdown(props.text));
             class="min-w-0 flex-1"
             :class="b.tasks?.[j]?.checked ? 'text-neutral-400 line-through' : ''"
           >
-            <MarkdownInline :tokens="it" />
+            <MarkdownInline :tokens="it" :tag-colors="tagColors" />
           </span>
         </div>
       </div>
       <ul v-else-if="b.type === 'ul'" class="list-disc space-y-0.5 pl-5">
-        <li v-for="(it, j) in b.items ?? []" :key="j"><MarkdownInline :tokens="it" /></li>
+        <li v-for="(it, j) in b.items ?? []" :key="j"><MarkdownInline :tokens="it" :tag-colors="tagColors" /></li>
       </ul>
       <ol v-else-if="b.type === 'ol'" class="list-decimal space-y-0.5 pl-5">
-        <li v-for="(it, j) in b.items ?? []" :key="j"><MarkdownInline :tokens="it" /></li>
+        <li v-for="(it, j) in b.items ?? []" :key="j"><MarkdownInline :tokens="it" :tag-colors="tagColors" /></li>
       </ol>
       <pre
         v-else-if="b.type === 'pre'"
         class="overflow-x-auto whitespace-pre-wrap rounded-md bg-black/5 p-2 font-mono text-xs dark:bg-white/10"
         >{{ b.value ?? "" }}</pre
       >
-      <p v-else class="whitespace-pre-wrap"><MarkdownInline :tokens="b.inline ?? []" /></p>
+      <p v-else class="whitespace-pre-wrap"><MarkdownInline :tokens="b.inline ?? []" :tag-colors="tagColors" /></p>
     </template>
   </div>
 </template>