Terminal file viewer/editor + per-window app-command lockdown (#60)

Clicking a file path in Claude's terminal output now opens the file in its own window with a CodeMirror 6 editor. The editor highlights the target line, live-reloads while the file changes, and saves explicitly with hash-based conflict detection. The viewer commands are gated by window label.

Every app command is now ACL-gated per window through a Tauri AppManifest. build.rs checks the handler list against the capability files and fails the build on any mismatch.

Co-Authored-By: Claude Opus 5.5 (1M context) <noreply@anthropic.com>

app/src/viewer/highlightLine.ts

@@ -0,0 +1,40 @@
+import { StateEffect, StateField, type Extension, type Text } from "@codemirror/state";
+import { Decoration, EditorView, type DecorationSet } from "@codemirror/view";
+
+export const setHighlight = StateEffect.define<{ from: number; to: number } | null>();
+
+const lineMark = Decoration.line({ class: "cm-triple-c-target" });
+
+export function lineRangeToPositions(doc: Text, from: number, to: number): { from: number; to: number } | null {
+  const clamp = (n: number) => Math.min(Math.max(1, Math.floor(n)), doc.lines);
+  const a = clamp(from);
+  const b = Math.max(a, clamp(to));
+  return { from: doc.line(a).from, to: doc.line(b).from };
+}
+
+export const highlightLineField = StateField.define<DecorationSet>({
+  create: () => Decoration.none,
+  update(value, tr) {
+    let next = value.map(tr.changes);
+    for (const e of tr.effects) {
+      if (!e.is(setHighlight)) continue;
+      if (e.value === null) { next = Decoration.none; continue; }
+      const range = lineRangeToPositions(tr.state.doc, e.value.from, e.value.to);
+      if (!range) { next = Decoration.none; continue; }
+      const marks = [];
+      for (let pos = range.from; pos <= range.to; ) {
+        const line = tr.state.doc.lineAt(pos);
+        marks.push(lineMark.range(line.from));
+        if (line.to + 1 > tr.state.doc.length) break;
+        pos = line.to + 1;
+      }
+      next = Decoration.set(marks, true);
+    }
+    return next;
+  },
+  provide: (f) => EditorView.decorations.from(f),
+});
+
+export function highlightExtension(): Extension {
+  return [highlightLineField];
+}