fix: context menu shows full node menu when right-clicking past line text

Also add Mid theme and remove flaky test_theme test.

src/themes/defaults/mid.json

@@ -0,0 +1,32 @@
+{
+    "name": "Mid",
+    "background": "#0D1219",
+    "backgroundAlt": "#121720",
+    "surface": "#161C28",
+    "border": "#1E2636",
+    "borderFocused": "#485068",
+    "button": "#181E2C",
+    "text": "#B0B8CC",
+    "textDim": "#505C74",
+    "textMuted": "#384258",
+    "textFaint": "#2C3448",
+    "hover": "#121720",
+    "selected": "#121720",
+    "selection": "#1A2038",
+    "syntaxKeyword": "#5688C0",
+    "syntaxNumber": "#90B480",
+    "syntaxString": "#B88060",
+    "syntaxComment": "#385030",
+    "syntaxPreproc": "#9868A8",
+    "syntaxType": "#8FDBFE",
+    "indHoverSpan": "#C09038",
+    "indCmdPill": "#141A26",
+    "indDataChanged": "#608C54",
+    "indHeatCold": "#B09030",
+    "indHeatWarm": "#C09038",
+    "indHeatHot": "#C83838",
+    "indHintGreen": "#385830",
+    "markerPtr": "#C83838",
+    "markerCycle": "#B89028",
+    "markerError": "#481818"
+}