Add a Captures tab showing screen captures from the task's agent

mac/Sources/Byre/Feed.swift

@@ -20,10 +20,19 @@ final class Listeners<T> {
     }
 }
 
+struct Capture: Identifiable {
+    let id: String
+    let tool: String
+    let note: String
+    let when: Date
+    let base64: String
+}
+
 @MainActor
 @Observable
 final class Feed {
     private(set) var events: [ByreEvent] = []
+    private(set) var captures: [Capture] = []
     private(set) var ready = false
     private(set) var inherited = 0
     let appended = Listeners<[ByreEvent]>()
@@ -31,6 +40,7 @@ final class Feed {
     @ObservationIgnored private var last: Int64 = 0
     @ObservationIgnored private var buffer: [ByreEvent] = []
     @ObservationIgnored private var scheduled = false
+    @ObservationIgnored private var toolNames: [String: String] = [:]
     @ObservationIgnored private let shown: () -> Bool
 
     init(shown: @escaping () -> Bool) {
@@ -66,6 +76,30 @@ final class Feed {
 
     func prepend(_ older: [ByreEvent]) {
         events.insert(contentsOf: older, at: 0)
+        captures.insert(contentsOf: findCaptures(older), at: 0)
+    }
+
+    private func findCaptures(_ batch: [ByreEvent]) -> [Capture] {
+        var found: [Capture] = []
+        for ev in batch {
+            let p = ev.payload.value
+            if ev.kind == "agent.tool_call" {
+                toolNames[jsString(p["id"])] = toolLabel(jsString(p["name"]))
+                continue
+            }
+            guard ev.kind == "agent.tool_result", let list = p["content"] as? [(any Sendable)?] else {
+                continue
+            }
+            let blocks = list.compactMap { $0 as? JSONDict }
+            let note = blocks.compactMap { str($0, "type") == "text" ? str($0, "text") : nil }.first ?? ""
+            for (i, b) in blocks.enumerated() {
+                guard str(b, "type") == "image", let source = dict(b, "source"), let data = str(source, "data") else {
+                    continue
+                }
+                found.append(Capture(id: "\(ev.seq)/\(i)", tool: toolNames[jsString(p["tool_use_id"])] ?? "", note: note, when: ev.createdAt, base64: data))
+            }
+        }
+        return found
     }
 
     private func flush() {
@@ -97,6 +131,10 @@ final class Feed {
             return
         }
         events.append(contentsOf: fresh)
+        let found = findCaptures(fresh)
+        if !found.isEmpty {
+            captures.append(contentsOf: found)
+        }
         if shown() {
             appended.send(fresh)
         }