feat(web): implement complete workspace with themes, tabs, sidebar, and mobile

Transform CalcText from a single-document calculator into a full workspace
application with multi-document support, theming, and responsive mobile experience.

- Theme system: 5 presets (Light, Dark, Matrix, Midnight, Warm) + accent colors
- Document model with localStorage persistence and auto-save
- Tab bar with keyboard shortcuts (Ctrl+N/W/Tab/1-9), rename, close
- Sidebar with search, recent, favorites, folders, templates, drag-and-drop
- 5 templates: Budget, Invoice, Unit Converter, Trip Planner, Loan Calculator
- Status bar with cursor position, engine status, dedication to Igor Cassel
- Results panel: type-specific colors, click-to-copy, error hints
- Format toolbar: H, B, I, //, color labels with live preview toggle
- Syntax highlighting using theme CSS variables
- Error hover tooltips
- Mobile: bottom results tray, sidebar drawer, touch targets, safe areas
- Docker multi-stage build (Rust WASM + Vite + Nginx)

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

calcpad-web/src/editor/inline-results.ts

@@ -0,0 +1,54 @@
+/**
+ * CodeMirror 6 extension for zebra-striped editor lines.
+ *
+ * Previously also contained inline result widgets, but results
+ * are now rendered in a separate ResultsPanel component.
+ */
+
+import { Decoration, EditorView, ViewPlugin } from '@codemirror/view'
+import type { DecorationSet, ViewUpdate } from '@codemirror/view'
+import type { Extension } from '@codemirror/state'
+
+/**
+ * ViewPlugin that applies alternating background colors (zebra striping)
+ * to even-numbered editor lines, helping users visually connect
+ * expressions on the left to their inline results on the right.
+ */
+export const stripedLines = ViewPlugin.fromClass(
+  class {
+    decorations: DecorationSet
+
+    constructor(view: EditorView) {
+      this.decorations = buildStripeDecorations(view)
+    }
+
+    update(update: ViewUpdate) {
+      if (update.docChanged || update.viewportChanged) {
+        this.decorations = buildStripeDecorations(update.view)
+      }
+    }
+  },
+  {
+    decorations: (v) => v.decorations,
+  },
+)
+
+const stripeDeco = Decoration.line({ class: 'cm-stripe' })
+
+function buildStripeDecorations(view: EditorView): DecorationSet {
+  const decorations: Array<ReturnType<typeof stripeDeco.range>> = []
+  for (let i = 1; i <= view.state.doc.lines; i++) {
+    if (i % 2 === 0) {
+      const line = view.state.doc.line(i)
+      decorations.push(stripeDeco.range(line.from))
+    }
+  }
+  return Decoration.set(decorations)
+}
+
+/**
+ * Creates the striped-lines extension for the editor.
+ */
+export function stripedLinesExtension(): Extension {
+  return [stripedLines]
+}