Add ?string= param to T1 note-prompter

T1 previously picked the string only from localStorage (default low E).
Accept an optional ?string= URL param (1 = high e … 6 = low E) so wiki
deep-links can pin the string explicitly; invalid values fall back to the
stored/default string.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

README.md

@@ -102,7 +102,8 @@ Optional query parameters override the stored/default settings:
 
 | Param      | Applies to            | Example        |
 |------------|-----------------------|----------------|
-| `bpm`      | click-track drills    | `?bpm=66`      |
+| `bpm`      | click-track drills, T1 | `?bpm=66`     |
+| `string`   | T1 (1 = high e … 6 = low E) | `?string=6` |
 | `variant`  | drills with variants  | `?variant=2-3-2` |
 | `key`      | T2, T4                | `?key=D`       |
 | `root`     | T3, T5, T6            | `?root=A`      |

src/components/views/NotePrompterView.svelte

@@ -15,7 +15,15 @@
   }
   let { drill, params }: Props = $props()
 
-  const initString = () => storage.getNumber(`${drill.code}:string`, 5)
+  // URL uses guitar string numbering (1 = high e … 6 = low E); internal index is 0 = high e … 5 = low E.
+  function stringFromParam(): number | null {
+    const q = params.get('string')
+    if (q === null) return null
+    const n = Number(q)
+    if (Number.isInteger(n) && n >= 1 && n <= 6) return n - 1
+    return null
+  }
+  const initString = () => stringFromParam() ?? storage.getNumber(`${drill.code}:string`, 5)
   const initRandom = () => storage.getString(`${drill.code}:order`, 'seq') === 'rand'
 
   let stringIdx = $state(initString())