feat(ios): P1-B — W7 UI wave: deep links, timeline, quick-reply, diff, projects, session switcher, thumbnails, lock-screen push

T-iOS-22: DeepLinkRouter (full-field whitelist, cold-start stash, route(from:) for push-tap reuse), 21 tests
T-iOS-24: TimelineSheet mirroring web render() order; disabled→empty-state; reuses AwayDigest onExpand
T-iOS-25: QuickReply chips (built-ins mirror quick-reply.ts via KeyByteMap; visible iff live gate && !readOnly)
T-iOS-27: read-only DiffScreen + App-layer DiffFetcher (RO no-Origin; APIClient fold-in noted for T-iOS-38 owner)
T-iOS-26: Projects list/detail — grouping byte-identical to web group keys (prefs-shared collapse state),
prefs-clobber defenses (no blind PUT on empty base; adopt server echo), claude\r bootstrap
T-iOS-23: UnreadLedger + TitleSanitizer (SessionCore, +15 tests), lastOutputAt decode, list-boundary re-sanitize
T-iOS-29: new-in-cwd (untrusted cwd, no bootstrap re-injection) + exited-session reopen; fixes stale-controller
SwiftTerm view bug via .id(controller.id)
T-iOS-28: offscreen SwiftTerm thumbnail pipeline (LRU 32, concurrency gate 2, 256KiB cap, grid clamp)
T-iOS-21: PushRegistrar (WEBTERM_GATE category: Allow=.authenticationRequired, no .foreground) +
NotificationActionHandler (whitelisted payload, token never persisted, bg-task-wrapped POST, 403 fallback)
CRITICAL fix (verify-found boot crash): @Sendable literals on UN completion closures — MainActor-inherited
closures trapped Swift 6 executor check on UN's background queue; boot re-verified (no new crash reports,
permission prompt reached, privacy shade correctly covering during system alert)
Verified: 261 pkg + 247 app + 10 integration tests green; 7/7 semantics checks; Owns audit clean

ios/App/WebTerm/Components/SessionThumbnailRenderer.swift

@@ -0,0 +1,85 @@
+import SwiftTerm
+import UIKit
+
+/// T-iOS-28 · 离屏 SwiftTerm 渲染器：把一段 preview tail（不可信 ANSI 字节，
+/// **只喂终端解释器，绝不字符串处理**）喂进一个从不进视图层级的
+/// `TerminalView`，再用 `UIGraphicsImageRenderer` 对已布局的 view 出快照。
+///
+/// 与 web 预览逐点对齐（public/preview-grid.ts makePreviewCard/renderPreview）：
+/// - 网格 = 服务器回报的 cols×rows（上游已钳制）——换行与真屏一致；
+/// - `scrollback: 0` ↔ `changeScrollback(nil)`：buffer 只有当前屏，
+///   `contentOffset` 恒为 0，离屏 draw 恰取「现在这一屏」；
+/// - 暗底主题 + 隐藏光标（web 用 cursor==background；此处喂 DECTCEM 隐藏序列，
+///   iOS 端直接把 caret 子视图摘掉）；
+/// - 快照按 `snapshotTargetWidth` 缩放——缓存的是小位图，不是整格点阵。
+///
+/// 生命周期：`TerminalView` 在初始化时向主 runloop 挂 CADisplayLink（暂停态），
+/// 离屏用完必须 `updateUiClosed()` 注销，否则每次渲染泄漏一个 runloop 源。
+@MainActor
+enum SessionThumbnailRenderer {
+    /// 快照宽度预算（pt）：列表槽位 88pt 的 2 倍，配 `snapshotScale`=2 后
+    /// 像素密度足够，单张缓存 ≈ 数百 KB 有界。
+    static let snapshotTargetWidth: CGFloat = 176
+    /// 固定 2x：快照是缩略图，不追设备 3x（内存 × 2.25 不值）。
+    static let snapshotScale: CGFloat = 2
+    /// 镜像 web 预览字号（public/preview-grid.ts fontSize: 12）。
+    static let fontSize: CGFloat = 12
+    /// 布局余量（pt）：frame 取 optimal + slack，抵消 `Int(width/cellW)` 的
+    /// 浮点截断——必须严格小于一个 cell 宽，否则网格会多出一列。
+    static let layoutSlack: CGFloat = 0.5
+    /// DECTCEM 隐藏光标（数据喂完后追加；iOS 端会摘掉 caret 子视图）。
+    /// 这是我们自己的常量序列，不是对服务器数据的处理。
+    static let hideCursorSequence = "\u{1b}[?25l"
+    /// 镜像 web PREVIEW_THEME（#0e0f13 / #e7e8ec）。
+    static let backgroundColor = UIColor(
+        red: 14 / 255, green: 15 / 255, blue: 19 / 255, alpha: 1
+    )
+    static let foregroundColor = UIColor(
+        red: 231 / 255, green: 232 / 255, blue: 236 / 255, alpha: 1
+    )
+    private static let initialProbeFrame = CGRect(x: 0, y: 0, width: 64, height: 64)
+
+    /// 渲染一张快照。`cols`/`rows` 必须已过 `clampedGeometry`（有界）；失败
+    /// 返回 nil（上游显式降级为占位图）。
+    static func render(data: String, cols: Int, rows: Int) -> UIImage? {
+        let font = UIFont.monospacedSystemFont(ofSize: fontSize, weight: .regular)
+        let terminal = TerminalView(frame: initialProbeFrame, font: font)
+        defer { terminal.updateUiClosed() } // 注销 CADisplayLink，绝不泄漏
+        terminal.changeScrollback(nil)      // ↔ web scrollback: 0
+        terminal.resize(cols: cols, rows: rows)
+        terminal.nativeBackgroundColor = backgroundColor
+        terminal.nativeForegroundColor = foregroundColor
+
+        let optimal = terminal.getOptimalFrameSize()
+        guard optimal.width > 0, optimal.height > 0 else { return nil }
+        terminal.frame = CGRect(
+            x: 0, y: 0,
+            width: optimal.width + layoutSlack, height: optimal.height + layoutSlack
+        )
+        terminal.layoutIfNeeded()
+
+        terminal.feed(text: data)              // 唯一合法去处：ANSI 解释器
+        terminal.feed(text: hideCursorSequence)
+
+        return snapshot(of: terminal, contentSize: optimal.size)
+    }
+
+    /// `UIGraphicsImageRenderer` + `layer.render(in:)`：离屏（无 window）视图
+    /// 走 CoreGraphics draw 路径（SwiftTerm 默认不启 Metal——Metal 层无法被
+    /// `layer.render` 捕获，此处也永不 `setUseMetal`）。
+    private static func snapshot(of view: UIView, contentSize: CGSize) -> UIImage? {
+        let scale = min(1, snapshotTargetWidth / contentSize.width)
+        let size = CGSize(
+            width: contentSize.width * scale, height: contentSize.height * scale
+        )
+        guard size.width >= 1, size.height >= 1 else { return nil }
+        let format = UIGraphicsImageRendererFormat()
+        format.scale = snapshotScale
+        format.opaque = true
+        let renderer = UIGraphicsImageRenderer(size: size, format: format)
+        return renderer.image { context in
+            context.cgContext.scaleBy(x: scale, y: scale)
+            view.layer.render(in: context.cgContext)
+        }
+    }
+}