feat(naming): add a narrators token to file naming patterns

Multiple audiobook editions of one title resolved to the same target path, so
enabling file rename merged or skipped every narrator but the first. Add
{narrators}, plus a :max3 modifier that yields nothing above three values, and
judge an optional group by what its placeholders render so the fallback literal
stays in the user's own pattern. The five duplicate token builders collapse into
one shared helper, which also gives audio uploads the metadata tokens they never
had. Build the shared types package before server lint, since type-aware rules
degrade to unknown on a clean checkout without it.

Refs #1108

packages/types/src/pattern-resolver.ts

@@ -9,6 +9,7 @@ export const EXAMPLE_PATTERN_METADATA: Record<string, string> = {
   title: "Neuromancer",
   subtitle: "20th Anniversary Edition",
   authors: "William Gibson",
+  narrators: "Robertson Dean",
   year: "1984",
   series: "Sprawl",
   seriesIndex: "01",
@@ -24,6 +25,7 @@ export const PATTERN_TOKENS = [
   { token: "title", description: "Book title" },
   { token: "subtitle", description: "Book subtitle" },
   { token: "authors", description: "Author(s), comma-separated" },
+  { token: "narrators", description: "Narrator(s), comma-separated" },
   { token: "year", description: "Publication year" },
   { token: "series", description: "Series name" },
   { token: "seriesIndex", description: "Series index (zero-padded)" },
@@ -90,6 +92,13 @@ export function applyModifier(value: string, modifier: string, fieldName: string
       }
       return target.charAt(0).toUpperCase();
     }
+    case "max3": {
+      const parts = value
+        .split(", ")
+        .map((part) => part.trim())
+        .filter(Boolean);
+      return parts.length > 3 ? "" : parts.join(", ");
+    }
     case "upper":
       return value.toUpperCase();
     case "lower":
@@ -113,7 +122,11 @@ function resolveModifierPlaceholders(block: string, values: Record<string, strin
 
 function checkAllPlaceholdersPresent(block: string, values: Record<string, string>): boolean {
   const matches = [...block.matchAll(MODIFIER_PLACEHOLDER_REGEX)];
-  return matches.every((m) => values[m[1]]?.trim());
+  return matches.every(([, fieldName, modifier]) => {
+    const raw = values[fieldName] ?? "";
+    if (!raw.trim()) return false;
+    return (modifier ? applyModifier(raw, modifier, fieldName) : raw).trim().length > 0;
+  });
 }
 
 export function replacePlaceholders(pattern: string, values: Record<string, string>): string {