chore: archive refactor milestones and remove structural quality-gates task

- Remove structural quality gates task and references from task-27 roadmap.
- Remove structural-gates-adjacent work from scripts/positioning cleanup context, including check-main-lines adjustments.
- Archive completed backlog tasks 11 and 27.7 by moving them to completed directory.
- Finish task-27.5 module split by moving/anonymizing anki-integration and renderer positioning files into their dedicated directories and updating paths.

src/renderer/positioning/position-state.ts

@@ -0,0 +1,136 @@
+import type { SubtitlePosition } from "../../types";
+import type { RendererContext } from "../context";
+
+const PREFERRED_Y_PERCENT_MIN = 2;
+const PREFERRED_Y_PERCENT_MAX = 80;
+
+export type SubtitlePositionController = {
+  applyStoredSubtitlePosition: (position: SubtitlePosition | null, source: string) => void;
+  getCurrentYPercent: () => number;
+  applyYPercent: (yPercent: number) => void;
+  persistSubtitlePositionPatch: (patch: Partial<SubtitlePosition>) => void;
+};
+
+function clampYPercent(yPercent: number): number {
+  return Math.max(PREFERRED_Y_PERCENT_MIN, Math.min(PREFERRED_Y_PERCENT_MAX, yPercent));
+}
+
+function getPersistedYPercent(
+  ctx: RendererContext,
+  position: SubtitlePosition | null,
+): number {
+  if (!position || typeof position.yPercent !== "number" || !Number.isFinite(position.yPercent)) {
+    return ctx.state.persistedSubtitlePosition.yPercent;
+  }
+
+  return position.yPercent;
+}
+
+function getPersistedOffset(
+  ctx: RendererContext,
+  position: SubtitlePosition | null,
+  key: "invisibleOffsetXPx" | "invisibleOffsetYPx",
+): number {
+  if (
+    position &&
+    typeof position[key] === "number" &&
+    Number.isFinite(position[key])
+  ) {
+    return position[key];
+  }
+
+  return 0;
+}
+
+function updatePersistedSubtitlePosition(
+  ctx: RendererContext,
+  position: SubtitlePosition | null,
+): void {
+  ctx.state.persistedSubtitlePosition = {
+    yPercent: getPersistedYPercent(ctx, position),
+    invisibleOffsetXPx: getPersistedOffset(ctx, position, "invisibleOffsetXPx"),
+    invisibleOffsetYPx: getPersistedOffset(ctx, position, "invisibleOffsetYPx"),
+  };
+}
+
+function getNextPersistedPosition(
+  ctx: RendererContext,
+  patch: Partial<SubtitlePosition>,
+): SubtitlePosition {
+  return {
+    yPercent:
+      typeof patch.yPercent === "number" && Number.isFinite(patch.yPercent)
+        ? patch.yPercent
+        : ctx.state.persistedSubtitlePosition.yPercent,
+    invisibleOffsetXPx:
+      typeof patch.invisibleOffsetXPx === "number" &&
+      Number.isFinite(patch.invisibleOffsetXPx)
+        ? patch.invisibleOffsetXPx
+        : ctx.state.persistedSubtitlePosition.invisibleOffsetXPx ?? 0,
+    invisibleOffsetYPx:
+      typeof patch.invisibleOffsetYPx === "number" &&
+      Number.isFinite(patch.invisibleOffsetYPx)
+        ? patch.invisibleOffsetYPx
+        : ctx.state.persistedSubtitlePosition.invisibleOffsetYPx ?? 0,
+  };
+}
+
+export function createInMemorySubtitlePositionController(
+  ctx: RendererContext,
+): SubtitlePositionController {
+  function getCurrentYPercent(): number {
+    if (ctx.state.currentYPercent !== null) {
+      return ctx.state.currentYPercent;
+    }
+
+    const marginBottom = parseFloat(ctx.dom.subtitleContainer.style.marginBottom) || 60;
+    ctx.state.currentYPercent = clampYPercent((marginBottom / window.innerHeight) * 100);
+    return ctx.state.currentYPercent;
+  }
+
+  function applyYPercent(yPercent: number): void {
+    const clampedPercent = clampYPercent(yPercent);
+    ctx.state.currentYPercent = clampedPercent;
+    const marginBottom = (clampedPercent / 100) * window.innerHeight;
+
+    ctx.dom.subtitleContainer.style.position = "";
+    ctx.dom.subtitleContainer.style.left = "";
+    ctx.dom.subtitleContainer.style.top = "";
+    ctx.dom.subtitleContainer.style.right = "";
+    ctx.dom.subtitleContainer.style.transform = "";
+    ctx.dom.subtitleContainer.style.marginBottom = `${marginBottom}px`;
+  }
+
+  function persistSubtitlePositionPatch(patch: Partial<SubtitlePosition>): void {
+    const nextPosition = getNextPersistedPosition(ctx, patch);
+    ctx.state.persistedSubtitlePosition = nextPosition;
+    window.electronAPI.saveSubtitlePosition(nextPosition);
+  }
+
+  function applyStoredSubtitlePosition(position: SubtitlePosition | null, source: string): void {
+    updatePersistedSubtitlePosition(ctx, position);
+    if (position && position.yPercent !== undefined) {
+      applyYPercent(position.yPercent);
+      console.log(
+        "Applied subtitle position from",
+        source,
+        ":",
+        position.yPercent,
+        "%",
+      );
+      return;
+    }
+
+    const defaultMarginBottom = 60;
+    const defaultYPercent = (defaultMarginBottom / window.innerHeight) * 100;
+    applyYPercent(defaultYPercent);
+    console.log("Applied default subtitle position from", source);
+  }
+
+  return {
+    applyStoredSubtitlePosition,
+    getCurrentYPercent,
+    applyYPercent,
+    persistSubtitlePositionPatch,
+  };
+}