lower time frame trendlines blocked from dma chart

docs/implementation.md

@@ -1094,6 +1094,12 @@ same effective style is applied to rare SVG endpoint bridges so an off-grid
 anchor cannot introduce a visible style seam. Browser coverage checks 30m-on-5m
 and native 30m rendering separately.
 
+Sloped manual lines also stop propagating upward: a 30m line is available on
+30m and lower charts but hidden on 1h/1d. This is a display filter only; the
+drawing remains loaded and flat price levels remain visible everywhere. The
+daily-chart regression creates a real 30m drawing, confirms it is rendered on
+the lower chart, switches to 1d, and requires only its series to disappear.
+
 ### 2026-08-15 — 1m zoom-out died at ~1am because the socket sent 1,000 bars
 
 Compressing the 1m time scale stopped around 01:00, then looked empty.

docs/plan.md

@@ -122,8 +122,10 @@ if your parser doesn't filter those, that fixture will catch it.
 1d    base chart + THE DAILY MAs         weight 16    ← a switchable base timeframe
 ```
 
-Base timeframe controls the candles only. **Every level stays visible on every base
-timeframe** — the 200DMA on a 1-minute chart is the point, not a side effect.
+Derived levels and flat price levels stay visible on every base timeframe — the
+200DMA on a 1-minute chart is the point, not a side effect. Sloped manual
+trendlines are visible on their attributed timeframe and lower charts, but not
+on higher charts: 30m structure belongs on 30m/15m/5m/1m, not on 1h or 1d.
 
 ---
 
@@ -917,8 +919,9 @@ LAYERS
 ☐ Hidden levels still count toward confluence
 ```
 
-- **The base timeframe switcher changes only the candles.** Every level stays on screen
-  — a 200DMA is equally valid on a 1m chart. That is the entire premise of the product.
+- **Derived and flat levels stay across base timeframes.** A 200DMA is equally
+  valid on a 1m chart. Sloped manual trendlines are the exception: hide them
+  above their attributed timeframe while retaining them on native/lower charts.
 - **The group checkbox is a master toggle** — unchecking "Daily MAs" hides all five at
   once; individual periods nest under it.
 - The colour swatch beside each timeframe is that timeframe's hue, used identically on

static/app.js

@@ -1347,7 +1347,8 @@ createApp({
     function enabled(level) {
       if (level.kind === 'ma') return (prefs.value.enabled.ma[level.tf] || []).includes(level.period);
       if (level.kind === 'manual') {
-        return prefs.value.enabled.drawings && prefs.value.enabled.manual;
+        return prefs.value.enabled.drawings && prefs.value.enabled.manual
+          && ConfluenceChart.manualLevelVisibleOn(level, timeframe.value);
       }
       if (level.kind === 'horizontal') return prefs.value.enabled.horizontal;
       if (level.kind === 'vwap') return prefs.value.enabled.vwap;

static/chart.js

@@ -1250,6 +1250,11 @@ class ConfluenceChart {
     return level.kind === 'ma' || level.kind === 'vwap' || level.kind === 'horizontal';
   }
 
+  static manualLevelVisibleOn(level, displayedTf) {
+    if (level.kind !== 'manual' || ConfluenceChart.isFlat(level)) return true;
+    return ConfluenceChart.tfRank[level.tf] >= ConfluenceChart.tfRank[displayedTf];
+  }
+
   manualLineDisplayStyle(level) {
     const baseWidth = level.line_width || 1;
     const displayedTf = this.bars[0]?.tf;

tests/e2e/trendline.test.mjs

@@ -358,6 +358,42 @@ test('higher-timeframe trendlines are dashed and twice their stored width',
     });
   });
 
+test('a lower-timeframe trendline is hidden from the daily chart',
+  { timeout: 180000 }, async () => {
+    await withChart(async page => {
+      const created = await page.evaluate(async () => {
+        const bars = (await (await fetch('/api/bars?tf=30m&limit=2')).json()).bars;
+        const first = bars[0];
+        const second = bars[1];
+        const response = await fetch('/api/lines', {
+          method: 'POST',
+          headers: { 'Content-Type': 'application/json' },
+          body: JSON.stringify({
+            tf: '30m', side: 'support', anchor_t: first.t, anchor_p: first.l,
+            end_t: second.t, end_p: first.l + 1, note: `daily filter ${Date.now()}`,
+          }),
+        });
+        return response.json();
+      });
+      await page.waitForFunction(id => window.__chart.levelSeries.has(id), created.id);
+
+      await page.click('.timeframes button:text-is("1d")');
+      await page.waitForFunction(() => window.__chart.bars[0]?.tf === '1d');
+      await page.waitForFunction(id => !window.__chart.levelSeries.has(id), created.id);
+      const state = await page.evaluate(async id => ({
+        drawingStillStored: (await (await fetch('/api/drawings')).json()).drawings
+          .some(drawing => drawing.id === id),
+        flatLevelVisible: ConfluenceChart.manualLevelVisibleOn(
+          { kind: 'manual', slope: 0, tf: '30m' }, '1d',
+        ),
+      }), created.id);
+
+      assert.equal(state.drawingStillStored, true, 'daily filtering deleted the drawing state');
+      assert.equal(state.flatLevelVisible, true, 'daily filtering hid a flat price level');
+      assertNoPageErrors(page, assert);
+    });
+  });
+
 test('a click, a move, then a click starts at the first click', { timeout: 180000 }, async () => {
   await withChart(async page => {
     const box = await chartBox(page);