Add SVG icons and TypeScript configuration files

- Introduced a new favicon.svg file for the application.
- Added icons.svg containing various SVG symbols for UI components.
- Created tsconfig.app.json for frontend TypeScript configuration with ES2023 target and bundler mode.
- Established tsconfig.json to reference app and node configurations.
- Implemented tsconfig.node.json for Node.js specific TypeScript settings.

docs/design_handoff_brainwave/docs/schema.md

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+# Practice Exam JSON Schema
+
+Upload a JSON file with this shape to load an exam.
+
+## Top-level
+
+```json
+{
+  "title": "string (required)",
+  "subtitle": "string (optional)",
+  "author": "string (optional)",
+  "timeLimitMinutes": 45,            // null or number
+  "feedbackMode": "end" | "immediate",
+  "passingScore": 70,                // percent
+  "categories": ["Topic 1", "Topic 2"],
+  "questions": [ /* see below */ ]
+}
+```
+
+## Common question fields
+
+```json
+{
+  "id": "q1",                        // required, unique
+  "type": "multiple-choice",         // see types below
+  "category": "Topic 1",
+  "points": 2,                       // default 1
+  "prompt": "Question text. LaTeX via $...$ and $$...$$",
+  "explanation": "Shown after grading",
+  "image":  { "src": "url", "alt": "...", "caption": "..." },
+  "audio":  { "src": "url" },
+  "code":   { "language": "python", "content": "..." },
+  "table":  { "headers": ["..."], "rows": [["..."]] },
+  "svg":    "<svg>...</svg>"
+}
+```
+
+## Question types
+
+| type | answer shape |
+|------|--------------|
+| `multiple-choice` | `"a"` — single choice id |
+| `multiple-select` | `["a", "c"]` — array of choice ids |
+| `short-answer`    | `"Paris"` with `acceptedForms`, `caseSensitive`, `ignorePunctuation`, `ignoreAccents` |
+| `math-input`      | LaTeX string; compared against `answer` + `acceptedForms` |
+| `translation`     | String; same options as short-answer plus `sourceLanguage`, `targetLanguage` |
+| `essay`           | No `answer`; optional `rubric` array + `minWords`. Self-graded. |
+| `match`           | `{ "l1": "r2", "l2": "r4" }` — left→right mapping |
+| `order`           | `["s1", "s2", "s3"]` — ordered item ids |