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/invisible-layout.ts

@@ -0,0 +1,90 @@
+import type { MpvSubtitleRenderMetrics } from "../../types";
+import type { RendererContext } from "../context";
+import {
+  applyContainerBaseLayout,
+  applyTypography,
+  applyVerticalPosition,
+} from "./invisible-layout-helpers.js";
+import {
+  calculateSubtitleMetrics,
+  calculateSubtitlePosition,
+} from "./invisible-layout-metrics.js";
+
+export type MpvSubtitleLayoutController = {
+  applyInvisibleSubtitleLayoutFromMpvMetrics: (metrics: MpvSubtitleRenderMetrics, source: string) => void;
+};
+
+export function createMpvSubtitleLayoutController(
+  ctx: RendererContext,
+  applySubtitleFontSize: (fontSize: number) => void,
+  options: {
+    applyInvisibleSubtitleOffsetPosition: () => void;
+    updateInvisiblePositionEditHud: () => void;
+  },
+): MpvSubtitleLayoutController {
+  function applyInvisibleSubtitleLayoutFromMpvMetrics(
+    metrics: MpvSubtitleRenderMetrics,
+    source: string,
+  ): void {
+    ctx.state.mpvSubtitleRenderMetrics = metrics;
+
+    const geometry = calculateSubtitleMetrics(ctx, metrics);
+    const alignment = calculateSubtitlePosition(metrics, geometry.pxPerScaledPixel, 2);
+
+    applySubtitleFontSize(geometry.effectiveFontSize);
+    const effectiveBorderSize = metrics.subBorderSize * geometry.pxPerScaledPixel;
+
+    document.documentElement.style.setProperty(
+      "--sub-border-size",
+      `${effectiveBorderSize}px`,
+    );
+
+    applyContainerBaseLayout(ctx, {
+      horizontalAvailable: Math.max(
+        0,
+        geometry.horizontalAvailable - Math.round(geometry.marginX * 2),
+      ),
+      leftInset: geometry.leftInset,
+      marginX: geometry.marginX,
+      hAlign: alignment.hAlign,
+    });
+
+    applyVerticalPosition(ctx, {
+      metrics,
+      renderAreaHeight: geometry.renderAreaHeight,
+      topInset: geometry.topInset,
+      bottomInset: geometry.bottomInset,
+      marginY: geometry.marginY,
+      effectiveFontSize: geometry.effectiveFontSize,
+      vAlign: alignment.vAlign,
+    });
+
+    applyTypography(ctx, {
+      metrics,
+      pxPerScaledPixel: geometry.pxPerScaledPixel,
+      effectiveFontSize: geometry.effectiveFontSize,
+    });
+
+    ctx.state.invisibleLayoutBaseLeftPx =
+      parseFloat(ctx.dom.subtitleContainer.style.left) || 0;
+
+    const parsedBottom = parseFloat(ctx.dom.subtitleContainer.style.bottom);
+    ctx.state.invisibleLayoutBaseBottomPx = Number.isFinite(parsedBottom)
+      ? parsedBottom
+      : null;
+
+    const parsedTop = parseFloat(ctx.dom.subtitleContainer.style.top);
+    ctx.state.invisibleLayoutBaseTopPx = Number.isFinite(parsedTop)
+      ? parsedTop
+      : null;
+
+    options.applyInvisibleSubtitleOffsetPosition();
+    options.updateInvisiblePositionEditHud();
+
+    console.log("[invisible-overlay] Applied mpv subtitle render metrics from", source);
+  }
+
+  return {
+    applyInvisibleSubtitleLayoutFromMpvMetrics,
+  };
+}