Speaker corrections: rename / merge / reassign + voice learning

Native editor to fix speaker-ID errors after transcription (modeled on recap-relay's
correction UX): rename a speaker in the legend, merge two speakers, or reassign an
individual transcript line. Saving rewrites speakers.json, re-renders transcript.md +
recap.html, and updates the voiceprint memory — so a correction compounds: naming an
"Unknown" speaker teaches that voice for future calls.

- SpeakerEditing (pure, tested): replaceSpeaker (rename = merge-onto-existing),
  reassign, netNameMap (compose ops), and remap (apply a name map to a recap's
  structured fields + whole-word free text, so summaries/extras update without re-LLM).
- RecapEditModel (@MainActor): loads speakers.json (+ optional recap.json +
  cluster_fingerprints.json); on save writes the resolved speakers.json, re-renders,
  and reconciles voiceprints — merge keeps the survivor's print; rename/name-an-Unknown
  enrolls the cluster's fingerprint under the new name.
- TranscriptEditorView (SwiftUI) + EditorWindow (AppKit window for the LSUIElement app);
  menu gains "Edit speakers".
- Pipeline now persists cluster_fingerprints.json (every cluster incl. Unknown) and
  recap.json (RecapFile) so the editor can learn voices + re-render offline.
- RecapModels made Codable; TranscriptAssembler exposes allFingerprints;
  VoiceprintStore gains enroll() + merge().

52/52 XCTest (6 new, incl. a full rename→artifacts→voiceprint round-trip on disk).

Ten31Transcripts/UI/EditorWindow.swift

@@ -0,0 +1,32 @@
+import AppKit
+import SwiftUI
+
+/// Hosts the speaker-correction editor in a standalone resizable window. A
+/// menu-bar (LSUIElement) app has no normal window scene, so we open one via
+/// AppKit and activate the app so it comes to the front.
+@MainActor
+final class EditorWindow {
+    static let shared = EditorWindow()
+    private var window: NSWindow?
+
+    func show(model: RecapEditModel) {
+        if let window {
+            window.contentViewController = NSHostingController(rootView: TranscriptEditorView(model: model))
+            window.title = model.title
+            NSApp.activate(ignoringOtherApps: true)
+            window.makeKeyAndOrderFront(nil)
+            return
+        }
+        let w = NSWindow(
+            contentRect: NSRect(x: 0, y: 0, width: 640, height: 560),
+            styleMask: [.titled, .closable, .resizable, .miniaturizable],
+            backing: .buffered, defer: false)
+        w.title = model.title
+        w.isReleasedWhenClosed = false
+        w.center()
+        w.contentViewController = NSHostingController(rootView: TranscriptEditorView(model: model))
+        window = w
+        NSApp.activate(ignoringOtherApps: true)
+        w.makeKeyAndOrderFront(nil)
+    }
+}