Build all apps from Markdown content; Compose Desktop replaces GTK on Linux and Windows

- content/ + scripts/build-content.py produce content.json for every app
- stable lesson IDs with one-time progress migration (Swift, Kotlin)
- shared answer-check tests (tests/answers.json) for Kotlin and Swift
- android/desktop: Compose app with updater, speech and GTK progress import
- CI packages AppImage and Windows zip with ProGuard, runs the tests

Co-authored-by: Cursor <cursoragent@cursor.com>

tests/swift/main.swift

@@ -0,0 +1,64 @@
+// Runs tests/answers.json against ios/Graduately/Data/Answers.swift, the same
+// cases the Kotlin apps check (android/desktop/src/test). Usage:
+//   swift-answers <tests/answers.json> <content.json>
+import Foundation
+
+let args = CommandLine.arguments
+guard args.count == 3,
+      let casesData = FileManager.default.contents(atPath: args[1]),
+      let cases = try? JSONSerialization.jsonObject(with: casesData) as? [String: Any],
+      let contentData = FileManager.default.contents(atPath: args[2]),
+      let content = try? JSONSerialization.jsonObject(with: contentData) as? [String: Any]
+else {
+    print("usage: swift-answers tests/answers.json content.json")
+    exit(2)
+}
+
+var failures = 0
+var checked = 0
+
+func rows(_ name: String) -> [[Any]] { cases[name] as? [[Any]] ?? [] }
+func str(_ v: Any) -> String? { v as? String }
+func points(_ v: Any) -> [(Int, Int)] { (v as? [[Int]] ?? []).map { ($0[0], $0[1]) } }
+
+func expect<T: Equatable>(_ got: T, _ want: T, _ what: String) {
+    checked += 1
+    if got != want {
+        failures += 1
+        print("FAIL \(what): got \(got), want \(want)")
+    }
+}
+
+for r in rows("normalize") { expect(normalizeAnswer(str(r[0])), str(r[1]) ?? "", "normalize \(r[0])") }
+for r in rows("accepts") { expect(answerAccepts(normalizeAnswer(str(r[0])), str(r[1])), r[2] as! Bool, "accepts \(r)") }
+for r in rows("incomplete") { expect(answerIncomplete(normalizeAnswer(str(r[0])), str(r[1])), r[2] as! Bool, "incomplete \(r)") }
+for r in rows("netTxtEq") { expect(netTxtEq(str(r[0]), str(r[1])), r[2] as! Bool, "netTxtEq \(r)") }
+for r in rows("hasUmlaut") { expect(hasUmlaut(str(r[0])), r[1] as! Bool, "hasUmlaut \(r)") }
+for r in rows("math") { expect(mathAnswerOk(str(r[0]), str(r[1])), r[2] as! Bool, "math \(r)") }
+for r in rows("drawNeed") { expect(mathDrawNeed(str(r[0])), r[1] as! Int, "drawNeed \(r)") }
+for r in rows("drawGiven") {
+    expect(mathDrawGiven(str(r[0])).map { "\($0.0),\($0.1)" }, points(r[1]).map { "\($0.0),\($0.1)" }, "drawGiven \(r)")
+}
+for r in rows("draw") { expect(mathDrawOk(str(r[0]), points(r[1])), r[2] as! Bool, "draw \(r)") }
+
+// Every worked answer in content/ must pass its own check.
+var problems = 0
+for section in ["mat0", "mat", "mat2", "mat3", "mat4"] {
+    for lesson in content[section] as? [[String: Any]] ?? [] {
+        for p in lesson["problems"] as? [[String: Any]] ?? [] {
+            guard let spec = p["answer"] as? String else { continue }
+            let at = "\(section) \(lesson["key"] ?? ""): \(spec)"
+            if mathIsDraw(spec) {
+                expect(mathDrawNeed(spec) > 0, true, at)
+            } else {
+                let body = spec.split(separator: ":", maxSplits: 1).last.map(String.init) ?? spec
+                expect(mathAnswerOk(spec, body.components(separatedBy: "|")[0]), true, at)
+            }
+            problems += 1
+        }
+    }
+}
+expect(problems > 100, true, "content has math problems")
+
+print("swift: \(checked - failures)/\(checked) ok")
+exit(failures == 0 ? 0 : 1)