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/stores/notes.ts

@@ -21,8 +21,13 @@ export interface NoteLabel {
   id: string;
   name: string;
   color: string;
-  // True when this label is attached because of a #tag in the note body (kept in
-  // sync with the text); false = added manually via the picker.
+  // True when the label is backed by text STILL IN THE BODY — a `#tag` written
+  // mid-sentence, kept in sync with those words. False covers both a label added
+  // through the picker and a tag lifted off a line of its own (M311), which is why
+  // it is also what decides whether a chip can be removed with a cross.
+  //
+  // The card reads it the other way round: a true here means the body is already
+  // showing this tag, so the chip would be the second copy and is not drawn.
   via_tag: boolean;
 }