feat(keyboard): add English QuickType bar and system lexicon

Show verbatim/correction/completion slots, mmap a 40k-word list, and
use UITextChecker plus supplementary lexicon for conservative autocorrect.

OSGKeyboardTests/AIUserSkillTests.swift

@@ -62,6 +62,86 @@ final class AIUserSkillTests: XCTestCase {
         XCTAssertEqual(catalog.entries.first?.shortcutName, "My Tasks")
     }
 
+    func testTextOnlySkillAllowsEmptyShortcutConfiguration() throws {
+        var catalog = AIUserSkillCatalog()
+        let skill = AIUserSkill(
+            name: "Rewrite",
+            prompt: "Rewrite the clipboard"
+        )
+
+        try catalog.upsert(skill)
+
+        let saved = try XCTUnwrap(catalog.entries.first)
+        let clipboardSkill = saved.asClipboardSkill()
+        XCTAssertNil(saved.shortcutICloudURL)
+        XCTAssertEqual(saved.shortcutName, "")
+        XCTAssertEqual(clipboardSkill.kind, .transform)
+        XCTAssertFalse(clipboardSkill.requiresShortcut)
+        XCTAssertNil(clipboardSkill.shortcutName)
+    }
+
+    func testShortcutNameWithoutLinkDoesNotExport() throws {
+        var catalog = AIUserSkillCatalog()
+        let skill = AIUserSkill(
+            name: "Rewrite",
+            prompt: "Rewrite the clipboard",
+            shortcutName: "Ignored without a link"
+        )
+
+        try catalog.upsert(skill)
+
+        let saved = try XCTUnwrap(catalog.entries.first)
+        XCTAssertEqual(saved.shortcutName, "Ignored without a link")
+        XCTAssertEqual(saved.asClipboardSkill().kind, .transform)
+        XCTAssertNil(saved.asClipboardSkill().shortcutName)
+    }
+
+    func testShortcutSkillRequiresNameAndValidShareLink() {
+        var catalog = AIUserSkillCatalog()
+        XCTAssertThrowsError(
+            try catalog.upsert(
+                AIUserSkill(
+                    name: "Export",
+                    prompt: "Export it",
+                    shortcutICloudURL: sampleURL
+                )
+            )
+        ) { error in
+            XCTAssertEqual(error as? AIUserSkillValidationError, .emptyShortcutName)
+        }
+
+        XCTAssertThrowsError(
+            try catalog.upsert(
+                AIUserSkill(
+                    name: "Export",
+                    prompt: "Export it",
+                    shortcutICloudURL: URL(string: "https://example.com/not-a-shortcut"),
+                    shortcutName: "Run Me"
+                )
+            )
+        ) { error in
+            XCTAssertEqual(error as? AIUserSkillValidationError, .invalidShortcutLink)
+        }
+    }
+
+    func testExistingShortcutSkillEncodingDecodesWithOptionalURL() throws {
+        let original = AIUserSkill(
+            name: "Export",
+            prompt: "Export it",
+            shortcutICloudURL: sampleURL,
+            shortcutName: "Run Me"
+        )
+
+        let decoded = try JSONDecoder().decode(
+            AIUserSkill.self,
+            from: JSONEncoder().encode(original)
+        )
+
+        XCTAssertEqual(decoded.shortcutICloudURL, sampleURL)
+        XCTAssertEqual(decoded.asClipboardSkill().kind, .export)
+        XCTAssertTrue(decoded.asClipboardSkill().requiresShortcut)
+    }
+
     func testThinkingDefaultsOffAndBuiltinCannotEnable() {
         let user = AIUserSkill(
             name: "Custom",
@@ -186,4 +266,45 @@ final class AIUserSkillStoreTests: XCTestCase {
         XCTAssertFalse(store.layout.hasConfirmedShortcut(skill.id))
         XCTAssertFalse(store.layout.isEnabled(skill.id))
     }
+
+    func testRemovingShortcutLinkKeepsEnabledTextSkill() throws {
+        let store = AIAgentSkillLayoutStore(defaults: makeDefaults())
+        var skill = AIUserSkill(
+            name: "Custom",
+            prompt: "Do it",
+            shortcutICloudURL: URL(
+                string: "https://www.icloud.com/shortcuts/65bf33ba4206484ba78d582eaf1e9c44"
+            ),
+            shortcutName: "Run Me"
+        )
+        try store.saveUserSkill(skill)
+        XCTAssertEqual(store.confirmShortcutAndEnable(skill.id), .enabled)
+
+        skill.shortcutICloudURL = nil
+        try store.saveUserSkill(skill)
+
+        XCTAssertTrue(store.layout.isEnabled(skill.id))
+        XCTAssertFalse(store.layout.hasConfirmedShortcut(skill.id))
+        XCTAssertEqual(store.userSkill(id: skill.id)?.asClipboardSkill().kind, .transform)
+    }
+
+    func testAddingShortcutLinkDisablesTextSkillUntilConfirmed() throws {
+        let store = AIAgentSkillLayoutStore(defaults: makeDefaults())
+        var skill = AIUserSkill(
+            name: "Custom",
+            prompt: "Do it"
+        )
+        try store.saveUserSkill(skill)
+        XCTAssertEqual(store.enable(skill.id), .enabled)
+
+        skill.shortcutICloudURL = URL(
+            string: "https://www.icloud.com/shortcuts/65bf33ba4206484ba78d582eaf1e9c44"
+        )
+        skill.shortcutName = "Run Me"
+        try store.saveUserSkill(skill)
+
+        XCTAssertFalse(store.layout.isEnabled(skill.id))
+        XCTAssertFalse(store.layout.hasConfirmedShortcut(skill.id))
+        XCTAssertEqual(store.enable(skill.id), .needsShortcut)
+    }
 }

OSGKeyboardTests/EnglishTypingOnDeviceTests.swift

@@ -0,0 +1,77 @@
+// EnglishTypingOnDeviceTests.swift
+// OSGKeyboardTests
+//
+// Hosted in the main app so these can run on a physical iPhone.
+// ExtTests stay tool-hosted (simulator-only).
+
+import XCTest
+@testable import OSGKeyboardShared
+
+final class EnglishTypingOnDeviceTests: XCTestCase {
+    func testLexiconLoadsFortyThousandWords() {
+        let lexicon = EnglishLexicon()
+        lexicon.prepare()
+        XCTAssertTrue(lexicon.isLoaded)
+        XCTAssertGreaterThanOrEqual(lexicon.wordCount, 30_000)
+        XCTAssertTrue(lexicon.contains("the"))
+        XCTAssertTrue(lexicon.contains("hello"))
+        XCTAssertTrue(lexicon.contains("definitely"))
+        lexicon.unload()
+        XCTAssertFalse(lexicon.isLoaded)
+    }
+
+    func testTehAutocorrectsToThe() {
+        let engine = EnglishSuggestionEngine()
+        engine.prepare()
+        XCTAssertEqual(
+            engine.correctionDecision(for: "teh", personalTerms: [], learnedBoosts: [:])?.replacement,
+            "the"
+        )
+    }
+
+    func testTitleCaseNamesStay() {
+        let engine = EnglishSuggestionEngine()
+        engine.prepare()
+        XCTAssertNil(engine.correctionDecision(for: "Rocky", personalTerms: [], learnedBoosts: [:]))
+        XCTAssertNil(engine.correctionDecision(for: "Wang", personalTerms: [], learnedBoosts: [:]))
+    }
+
+    func testProximityGppdBecomesGood() {
+        let engine = EnglishSuggestionEngine()
+        engine.prepare()
+        XCTAssertEqual(
+            engine.correctionDecision(for: "gppd", personalTerms: [], learnedBoosts: [:])?.replacement,
+            "good"
+        )
+    }
+
+    func testFormIsNotCorrectedToFrom() {
+        let engine = EnglishSuggestionEngine()
+        engine.prepare()
+        XCTAssertNil(engine.correctionDecision(for: "form", personalTerms: [], learnedBoosts: [:]))
+    }
+
+    func testThankYouBigram() {
+        let lexicon = EnglishLexicon()
+        lexicon.prepare()
+        XCTAssertTrue(lexicon.nextWords(after: "thank").contains("you"))
+    }
+
+    @MainActor
+    func testUITextCheckerCompletionsAvailable() {
+        let system = UIKitEnglishSystemLexicon()
+        let hits = system.completions(prefix: "hel", limit: 6)
+        XCTAssertFalse(hits.isEmpty, "device UITextChecker should complete hel")
+    }
+
+    @MainActor
+    func testQuickTypeBoardMarksCorrection() {
+        let engine = EnglishSuggestionEngine()
+        engine.prepare()
+        let composition = engine.compositionWhileTyping(
+            EnglishSuggestionContext(currentWord: "teh")
+        )
+        XCTAssertEqual(composition.candidates.first?.role, .verbatim)
+        XCTAssertTrue(composition.candidates.contains { $0.role == .correction && $0.text == "the" })
+    }
+}