feat: integrate n+1 target highlighting

- Merge feature branch changes for n+1 target-only highlight flow

- Extend merged token model and token-merger to mark exactly-one unknown targets

- Thread n+1 candidate metadata through tokenizer and config systems

- Update subtitle renderer/state to route configured colors and new token class

- Resolve merge conflicts in core service tests, including subtitle and subsync behavior

src/config/config.test.ts

@@ -186,6 +186,63 @@ test("accepts valid ankiConnect n+1 match mode values", () => {
   assert.equal(config.ankiConnect.nPlusOne.matchMode, "surface");
 });
 
+test("validates ankiConnect n+1 color values", () => {
+  const dir = makeTempDir();
+  fs.writeFileSync(
+    path.join(dir, "config.jsonc"),
+    `{
+      "ankiConnect": {
+        "nPlusOne": {
+          "nPlusOne": "not-a-color",
+          "knownWord": 123
+        }
+      }
+    }`,
+    "utf-8",
+  );
+
+  const service = new ConfigService(dir);
+  const config = service.getConfig();
+  const warnings = service.getWarnings();
+
+  assert.equal(
+    config.ankiConnect.nPlusOne.nPlusOne,
+    DEFAULT_CONFIG.ankiConnect.nPlusOne.nPlusOne,
+  );
+  assert.equal(
+    config.ankiConnect.nPlusOne.knownWord,
+    DEFAULT_CONFIG.ankiConnect.nPlusOne.knownWord,
+  );
+  assert.ok(
+    warnings.some((warning) => warning.path === "ankiConnect.nPlusOne.nPlusOne"),
+  );
+  assert.ok(
+    warnings.some((warning) => warning.path === "ankiConnect.nPlusOne.knownWord"),
+  );
+});
+
+test("accepts valid ankiConnect n+1 color values", () => {
+  const dir = makeTempDir();
+  fs.writeFileSync(
+    path.join(dir, "config.jsonc"),
+    `{
+      "ankiConnect": {
+        "nPlusOne": {
+          "nPlusOne": "#c6a0f6",
+          "knownWord": "#a6da95"
+        }
+      }
+    }`,
+    "utf-8",
+  );
+
+  const service = new ConfigService(dir);
+  const config = service.getConfig();
+
+  assert.equal(config.ankiConnect.nPlusOne.nPlusOne, "#c6a0f6");
+  assert.equal(config.ankiConnect.nPlusOne.knownWord, "#a6da95");
+});
+
 test("supports legacy ankiConnect.behavior N+1 settings as fallback", () => {
   const dir = makeTempDir();
   fs.writeFileSync(
@@ -268,5 +325,8 @@ test("template generator includes known keys", () => {
   assert.match(output, /"ankiConnect":/);
   assert.match(output, /"websocket":/);
   assert.match(output, /"youtubeSubgen":/);
+  assert.match(output, /"nPlusOne"\s*:\s*\{/);
+  assert.match(output, /"nPlusOne": "#c6a0f6"/);
+  assert.match(output, /"knownWord": "#a6da95"/);
   assert.match(output, /auto-generated from src\/config\/definitions.ts/);
 });

src/config/definitions.ts

@@ -128,6 +128,8 @@ export const DEFAULT_CONFIG: ResolvedConfig = {
       refreshMinutes: 1440,
       matchMode: "headword",
       decks: [],
+      nPlusOne: "#c6a0f6",
+      knownWord: "#a6da95",
     },
     metadata: {
       pattern: "[SubMiner] %f (%t)",
@@ -179,6 +181,8 @@ export const DEFAULT_CONFIG: ResolvedConfig = {
     fontWeight: "normal",
     fontStyle: "normal",
     backgroundColor: "rgba(54, 58, 79, 0.5)",
+    nPlusOneColor: "#c6a0f6",
+    knownWordColor: "#a6da95",
     secondary: {
       fontSize: 24,
       fontColor: "#ffffff",
@@ -321,6 +325,18 @@ export const CONFIG_OPTION_REGISTRY: ConfigOptionRegistryEntry[] = [
     description:
       "Decks used for N+1 known-word cache scope. Supports one or more deck names.",
   },
+  {
+    path: "ankiConnect.nPlusOne.nPlusOne",
+    kind: "string",
+    defaultValue: DEFAULT_CONFIG.ankiConnect.nPlusOne.nPlusOne,
+    description: "Color used for the single N+1 target token highlight.",
+  },
+  {
+    path: "ankiConnect.nPlusOne.knownWord",
+    kind: "string",
+    defaultValue: DEFAULT_CONFIG.ankiConnect.nPlusOne.knownWord,
+    description: "Color used for legacy known-word highlights.",
+  },
   {
     path: "ankiConnect.isKiku.fieldGrouping",
     kind: "enum",

src/config/service.ts

@@ -36,6 +36,15 @@ function asBoolean(value: unknown): boolean | undefined {
   return typeof value === "boolean" ? value : undefined;
 }
 
+const hexColorPattern =
+  /^#(?:[0-9a-fA-F]{3}|[0-9a-fA-F]{4}|[0-9a-fA-F]{6}|[0-9a-fA-F]{8})$/;
+
+function asColor(value: unknown): string | undefined {
+  if (typeof value !== "string") return undefined;
+  const text = value.trim();
+  return hexColorPattern.test(text) ? text : undefined;
+}
+
 export class ConfigService {
   private readonly configDir: string;
   private readonly configFileJsonc: string;
@@ -751,6 +760,34 @@ export class ConfigService {
         resolved.ankiConnect.nPlusOne.decks = [];
       }
 
+      const nPlusOneHighlightColor = asColor(nPlusOneConfig.nPlusOne);
+      if (nPlusOneHighlightColor !== undefined) {
+        resolved.ankiConnect.nPlusOne.nPlusOne = nPlusOneHighlightColor;
+      } else if (nPlusOneConfig.nPlusOne !== undefined) {
+        warn(
+          "ankiConnect.nPlusOne.nPlusOne",
+          nPlusOneConfig.nPlusOne,
+          resolved.ankiConnect.nPlusOne.nPlusOne,
+          "Expected a hex color value.",
+        );
+        resolved.ankiConnect.nPlusOne.nPlusOne =
+          DEFAULT_CONFIG.ankiConnect.nPlusOne.nPlusOne;
+      }
+
+      const nPlusOneKnownWordColor = asColor(nPlusOneConfig.knownWord);
+      if (nPlusOneKnownWordColor !== undefined) {
+        resolved.ankiConnect.nPlusOne.knownWord = nPlusOneKnownWordColor;
+      } else if (nPlusOneConfig.knownWord !== undefined) {
+        warn(
+          "ankiConnect.nPlusOne.knownWord",
+          nPlusOneConfig.knownWord,
+          resolved.ankiConnect.nPlusOne.knownWord,
+          "Expected a hex color value.",
+        );
+        resolved.ankiConnect.nPlusOne.knownWord =
+          DEFAULT_CONFIG.ankiConnect.nPlusOne.knownWord;
+      }
+
       if (
         resolved.ankiConnect.isKiku.fieldGrouping !== "auto" &&
         resolved.ankiConnect.isKiku.fieldGrouping !== "manual" &&