Fixes #34 — drop AI-generated images from verb vocab practice

Image Playground's .illustration style can't depict abstract verbs —
"dar" (to give) generated a Shiba Inu in a meadow, "saber" a cake.
Verbs are actions, not objects; a static illustration rarely helps and
the irrelevant output was pure noise.

Removed:
  - VerbIllustration view (was in VocabFlashcardPracticeView).
  - VocabImageService.swift entirely — VerbIllustration was its only
    consumer.
  - vocabImageService from the app environment in ConjugaApp.
  - The illustration row from both vocab session reveal panes.

Vocab card reveal is now: Spanish infinitive + example sentence +
rating buttons. The example sentence already carries the learning
context.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

Conjuga/Conjuga.xcodeproj/project.pbxproj

@@ -18,7 +18,6 @@
 		14242FD1F500D296D41E927C /* FeatureReferenceView.swift in Sources */ = {isa = PBXBuildFile; fileRef = 1C3E36BDC2540AF2A67AEEB1 /* FeatureReferenceView.swift */; };
 		1A230C01A045F0C095BFBD35 /* PracticeView.swift in Sources */ = {isa = PBXBuildFile; fileRef = 1EA0FA4F9149B9D8E197ADE9 /* PracticeView.swift */; };
 		1C2636790E70B6BC7FFCC904 /* DailyLog.swift in Sources */ = {isa = PBXBuildFile; fileRef = 0313D24F96E6A0039C34341F /* DailyLog.swift */; };
-		200E933E672F8B011DC16769 /* VocabImageService.swift in Sources */ = {isa = PBXBuildFile; fileRef = 3148F06ABA1BFCA36CB21E15 /* VocabImageService.swift */; };
 		20B71403A8D305C29C73ADA2 /* StemChangeConjugationView.swift in Sources */ = {isa = PBXBuildFile; fileRef = F92BCE1A6720E47FCD26BADC /* StemChangeConjugationView.swift */; };
 		218E982FC4267949F82AABAD /* SharedModels in Frameworks */ = {isa = PBXBuildFile; productRef = 4A4D7B02884EBA9ACD93F0FD /* SharedModels */; };
 		261E582449BED6EF41881B04 /* AdaptiveContainer.swift in Sources */ = {isa = PBXBuildFile; fileRef = 3B16FF4C52457CD8CD703532 /* AdaptiveContainer.swift */; };
@@ -179,7 +178,6 @@
 		2889F2F81673AFF3A58A07A8 /* WidgetDataReader.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = WidgetDataReader.swift; sourceTree = "<group>"; };
 		2931634BEB33B93429CE254F /* VocabFlashcardView.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = VocabFlashcardView.swift; sourceTree = "<group>"; };
 		30EF2362D9FFF9B07A45CE6D /* StreakCalendarView.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = StreakCalendarView.swift; sourceTree = "<group>"; };
-		3148F06ABA1BFCA36CB21E15 /* VocabImageService.swift */ = {isa = PBXFileReference; includeInIndex = 1; lastKnownFileType = sourcecode.swift; path = VocabImageService.swift; sourceTree = "<group>"; };
 		340B1F22929DC7C1DEB0EA8A /* BookLibraryView.swift */ = {isa = PBXFileReference; includeInIndex = 1; lastKnownFileType = sourcecode.swift; path = BookLibraryView.swift; sourceTree = "<group>"; };
 		34C67DD1A1CB9B8B5A2BDCED /* CheckpointExamView.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = CheckpointExamView.swift; sourceTree = "<group>"; };
 		3540936F058728CFD87B1A1E /* textbook_vocab.json */ = {isa = PBXFileReference; lastKnownFileType = text.json; path = textbook_vocab.json; sourceTree = "<group>"; };
@@ -368,7 +366,6 @@
 				AFF65B05E7CEC386F121973E /* YouTubeVideoStore.swift */,
 				221920B9BD6DC6F084093975 /* ExtraStudyStore.swift */,
 				A661ADF1141176EE96774138 /* BookSpeechController.swift */,
-				3148F06ABA1BFCA36CB21E15 /* VocabImageService.swift */,
 				A2ACC4C35491174257770941 /* VerbReviewStore.swift */,
 			);
 			path = Services;
@@ -799,7 +796,6 @@
 				33BFEC0F0DEFC8A0E1FD8009 /* BookSpeechController.swift in Sources */,
 				2CB1E7454C1C04C2A9A06D57 /* BookVoicePickerSheet.swift in Sources */,
 				C3F567971CE8379CCC0AA9ED /* GuideCrossLinks.swift in Sources */,
-				200E933E672F8B011DC16769 /* VocabImageService.swift in Sources */,
 				419DF099F0270E65D53932FD /* VocabFlashcardPracticeView.swift in Sources */,
 				12117B0704F799292AF1DBB6 /* VocabMultipleChoicePracticeView.swift in Sources */,
 				5D8A5E1ED1BE4F86A9907FA7 /* VerbReviewStore.swift in Sources */,

Conjuga/Conjuga/ConjugaApp.swift

@@ -43,7 +43,6 @@ struct ConjugaApp: App {
     @State private var verbExampleCache = VerbExampleCache()
     @State private var reflexiveStore = ReflexiveVerbStore()
     @State private var youtubeVideoStore = YouTubeVideoStore()
-    @State private var vocabImageService = VocabImageService()
 
     let localContainer: ModelContainer
     let cloudContainer: ModelContainer
@@ -120,7 +119,6 @@ struct ConjugaApp: App {
             .environment(verbExampleCache)
             .environment(reflexiveStore)
             .environment(youtubeVideoStore)
-            .environment(vocabImageService)
             .task {
                 let needsSeed = await DataLoader.needsSeeding(container: localContainer)
                 if needsSeed {

Conjuga/Conjuga/Services/VocabImageService.swift

@@ -1,134 +0,0 @@
-import CryptoKit
-import Foundation
-import ImagePlayground
-import SwiftUI
-import UIKit
-
-/// On-device illustrative images for vocab cards, via Apple Intelligence
-/// Image Playground (iOS 18.2+). Generated once per (deck, ES, EN) tuple,
-/// cached to disk in the app's Caches directory.
-///
-/// On devices/versions without Image Playground the service still works —
-/// it just always returns nil and the calling view falls back to a placeholder.
-@MainActor
-@Observable
-final class VocabImageService {
-    private let cacheRoot: URL = {
-        let caches = FileManager.default.urls(for: .cachesDirectory, in: .userDomainMask)[0]
-        let dir = caches.appendingPathComponent("VocabImages", isDirectory: true)
-        try? FileManager.default.createDirectory(at: dir, withIntermediateDirectories: true)
-        return dir
-    }()
-
-    /// In-flight generations keyed by cache key so callers asking for the same
-    /// image while it's being produced share the same task.
-    private var inFlight: [String: Task<UIImage?, Never>] = [:]
-
-    /// Look up a cached image synchronously. Returns nil if not yet generated.
-    func cachedImage(forKey key: String) -> UIImage? {
-        let url = cacheFileURL(forKey: key)
-        guard FileManager.default.fileExists(atPath: url.path) else { return nil }
-        return UIImage(contentsOfFile: url.path)
-    }
-
-    /// Generate (or fetch cached) image for the given English concept.
-    /// Returns nil on unsupported devices or if generation fails.
-    func image(
-        forKey key: String,
-        concept englishConcept: String
-    ) async -> UIImage? {
-        if let cached = cachedImage(forKey: key) {
-            return cached
-        }
-        if let existing = inFlight[key] {
-            return await existing.value
-        }
-        let task = Task<UIImage?, Never> { [cacheRoot] in
-            await Self.generate(concept: englishConcept, savingTo: Self.fileURL(in: cacheRoot, forKey: key))
-        }
-        inFlight[key] = task
-        let result = await task.value
-        inFlight[key] = nil
-        return result
-    }
-
-    /// Stable cache key for a vocab card. Hash so it survives weird characters
-    /// in the front/back text.
-    static func cacheKey(deckId: String, spanish: String, english: String) -> String {
-        let raw = "\(deckId)|\(spanish)|\(english)"
-        let digest = SHA256.hash(data: Data(raw.utf8))
-        return digest.map { String(format: "%02x", $0) }.joined()
-    }
-
-    /// Cached result of a one-time probe — true if `ImageCreator()` succeeds
-    /// on this device. Apple Intelligence only lights up on compatible
-    /// hardware + when the user has it enabled in Settings; `ImageCreator()`
-    /// throws otherwise.
-    nonisolated(unsafe) private static var probedAvailability: Bool? = nil
-    nonisolated(unsafe) private static let probeLock = NSLock()
-
-    /// Whether on-device image generation is available. Cached after first call.
-    static var isAvailable: Bool {
-        probeLock.lock()
-        defer { probeLock.unlock() }
-        if let cached = probedAvailability { return cached }
-        // Synchronous probe via Task isn't possible here; default to true on
-        // iOS 18.2+ and let the first actual generation succeed-or-fail
-        // produce the real signal. Older OS = never available.
-        guard #available(iOS 18.2, *) else {
-            probedAvailability = false
-            return false
-        }
-        return true
-    }
-
-    /// Mark the service as unavailable based on a real failure (called from
-    /// `generate(...)` when ImageCreator() init throws).
-    private static func markUnavailable() {
-        probeLock.lock()
-        probedAvailability = false
-        probeLock.unlock()
-    }
-
-    // MARK: - Internal
-
-    private func cacheFileURL(forKey key: String) -> URL {
-        Self.fileURL(in: cacheRoot, forKey: key)
-    }
-
-    private static func fileURL(in root: URL, forKey key: String) -> URL {
-        root.appendingPathComponent("\(key).png")
-    }
-
-    private static func generate(concept: String, savingTo destination: URL) async -> UIImage? {
-        guard #available(iOS 18.2, *) else { return nil }
-
-        let creator: ImageCreator
-        do {
-            creator = try await ImageCreator()
-        } catch {
-            print("[VocabImageService] ImageCreator unavailable: \(error)")
-            markUnavailable()
-            return nil
-        }
-
-        let sequence = creator.images(
-            for: [.text(concept)],
-            style: .illustration,
-            limit: 1
-        )
-        do {
-            for try await result in sequence {
-                let cgImage = result.cgImage
-                let uiImage = UIImage(cgImage: cgImage)
-                if let png = uiImage.pngData() {
-                    try? png.write(to: destination, options: .atomic)
-                }
-                return uiImage
-            }
-        } catch {
-            print("[VocabImageService] generation failed: \(error)")
-        }
-        return nil
-    }
-}

Conjuga/Conjuga/Views/Practice/Vocab/VocabFlashcardPracticeView.swift

@@ -104,8 +104,6 @@ struct VocabFlashcardPracticeView: View {
                 .font(.title.weight(.semibold))
                 .multilineTextAlignment(.center)
 
-            VerbIllustration(verb: verb)
-
             exampleBlock(for: verb)
 
             ratingButtons
@@ -279,81 +277,3 @@ enum VocabVerbPool {
         return pool.shuffled()
     }
 }
-
-// MARK: - Verb illustration
-
-/// AI-generated image for the verb's English concept. Generates on first
-/// reveal and caches to disk. Falls back to a styled SF Symbol when Image
-/// Playground is unavailable.
-struct VerbIllustration: View {
-    let verb: Verb
-
-    @Environment(VocabImageService.self) private var service
-    @State private var image: UIImage?
-    @State private var isGenerating: Bool = false
-
-    private var cacheKey: String {
-        VocabImageService.cacheKey(
-            deckId: "verb",
-            spanish: verb.infinitive,
-            english: verb.english
-        )
-    }
-
-    var body: some View {
-        ZStack {
-            RoundedRectangle(cornerRadius: 16)
-                .fill(.purple.opacity(0.08))
-                .frame(height: 200)
-
-            if let image {
-                Image(uiImage: image)
-                    .resizable()
-                    .scaledToFit()
-                    .frame(maxHeight: 200)
-                    .clipShape(RoundedRectangle(cornerRadius: 16))
-            } else if isGenerating {
-                VStack(spacing: 6) {
-                    ProgressView()
-                    Text("Generating illustration…")
-                        .font(.caption2)
-                        .foregroundStyle(.secondary)
-                }
-            } else if !VocabImageService.isAvailable {
-                placeholder
-            } else {
-                ProgressView()
-            }
-        }
-        .frame(maxWidth: .infinity)
-        .task(id: cacheKey, loadImage)
-    }
-
-    private var placeholder: some View {
-        VStack(spacing: 6) {
-            Image(systemName: "photo")
-                .font(.title2)
-                .foregroundStyle(.purple.opacity(0.55))
-            Text("Image generation unavailable on this device")
-                .font(.caption2)
-                .foregroundStyle(.secondary)
-                .multilineTextAlignment(.center)
-                .padding(.horizontal, 24)
-        }
-    }
-
-    @Sendable
-    private func loadImage() async {
-        if let cached = service.cachedImage(forKey: cacheKey) {
-            image = cached
-            return
-        }
-        guard VocabImageService.isAvailable else { return }
-        isGenerating = true
-        let result = await service.image(forKey: cacheKey, concept: verb.english)
-        isGenerating = false
-        if let result {
-            image = result
-        }
-    }
-}

Conjuga/Conjuga/Views/Practice/Vocab/VocabMultipleChoicePracticeView.swift

@@ -95,7 +95,6 @@ struct VocabMultipleChoicePracticeView: View {
     private func revealedContent(_ verb: Verb) -> some View {
         VStack(spacing: 16) {
             answerFeedback(verb)
-            VerbIllustration(verb: verb)
             exampleBlock(for: verb)
             ratingButtons
         }