feat(tauri): add unpack logs viewer for unrar attempts

Captures stdout, stderr, exit status and start/finish timestamps for every
unrar sidecar invocation and exposes them through a dedicated "Unpack Logs"
window. Triggered by the need to debug why a particular game's archive
failed to extract -- previously the only artifact of a failed unpack was a
log line in the Tauri process stdout, which is awkward to inspect on an
end-user machine.

Implementation:

* `LanSpreadState` gains an in-memory ring buffer (`unpack_logs`) capped at
  `MAX_UNPACK_LOGS` (100). The previous monolithic `do_unrar` is split into
  `prepare_unrar_paths` and `run_unrar_sidecar` so every failure path (mkdir
  failure, canonicalize failure, non-UTF-8 destination, sidecar spawn error,
  non-zero exit) records an `UnpackLogEntry` before bailing.
* A `get_unpack_logs` Tauri command returns the current snapshot; an
  `unpack-logs-updated` event is emitted after every write so the viewer can
  refresh without polling.
* The React `App` component now routes on `?view=unpack-logs` and renders a
  dedicated `UnpackLogsWindow`. The main window opens the viewer via
  `WebviewWindow` with label `unpack-logs`; an existing window is focused
  instead of being recreated.

Capability scoping: the new window is given its own capability file
(`capabilities/unpack-logs.json`) granting only `core:default`. The main
capability is unchanged in window scope and only gains the two permissions
the main window itself needs (`core:window:allow-set-focus` to focus an
existing log window, `core:webview:allow-create-webview-window` to spawn
it). Splitting the capability keeps the log window from inheriting
`shell:allow-open`, `dialog:default` and `store:default`, which it has no
reason to use.

Known limitations (intentionally out of scope here):

* Logs are process-local; they vanish on app restart. Persistence can be
  added later if it turns out users want to inspect failures across runs.
* Entries are presented as a flat chronological list identified by archive
  path. No per-game grouping or filtering yet -- the archive filename is
  usually enough to identify the game in practice.
* The `unpack-logs-updated` event carries no payload; the viewer re-fetches
  the full snapshot on every notification. Acceptable given the 100-entry
  cap, but a payload-bearing event would be cheaper if the cap grows.

Test plan:

* `just clippy` and `just build` are clean.
* Manual: start the GUI, point it at a games directory containing at least
  one peer-hosted game, trigger an install, then click "Unpack Logs". The
  window should show one entry per unrar invocation with stdout, stderr,
  status code and timestamps; stderr/error lines render in the warning
  color. Triggering further unpacks should update the open window live via
  the `unpack-logs-updated` event without manual refresh.
* Negative path: rename or remove the archive between handshake and
  extraction to force a canonicalize failure; confirm a failed entry with
  the corresponding stderr appears in the viewer.

Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>

crates/lanspread-tauri-deno-ts/src/App.css

@@ -349,3 +349,80 @@ h1.align-center {
     left: 20px;
     z-index: 1001;
 }
+
+.unpack-log-window {
+    min-height: 100vh;
+    box-sizing: border-box;
+    padding: 18px;
+    background: #000313;
+    color: #D5DBFE;
+}
+
+.unpack-log-header {
+    display: flex;
+    align-items: center;
+    justify-content: space-between;
+    gap: 16px;
+    margin-bottom: 14px;
+}
+
+.unpack-log-header h1 {
+    margin: 0;
+    font-size: 22px;
+}
+
+.unpack-log-textfield {
+    height: calc(100vh - 84px);
+    box-sizing: border-box;
+    overflow: auto;
+    padding: 14px;
+    border: 1px solid #444;
+    border-radius: 6px;
+    background: #050813;
+    font-family: Consolas, "Courier New", monospace;
+    font-size: 13px;
+    line-height: 1.35;
+    white-space: pre-wrap;
+}
+
+.unpack-log-empty {
+    color: #8892b0;
+}
+
+.unpack-log-entry {
+    padding-bottom: 16px;
+    margin-bottom: 16px;
+    border-bottom: 1px solid #26304f;
+}
+
+.unpack-log-entry:last-child {
+    margin-bottom: 0;
+    border-bottom: 0;
+}
+
+.unpack-log-meta {
+    margin-bottom: 6px;
+    font-weight: bold;
+}
+
+.unpack-log-meta.success {
+    color: #8ee6a6;
+}
+
+.unpack-log-meta.error,
+.unpack-log-stream.stderr {
+    color: #ff8a8a;
+}
+
+.unpack-log-path {
+    color: #aeb7df;
+}
+
+.unpack-log-stream {
+    margin: 8px 0 0;
+    font: inherit;
+}
+
+.unpack-log-stream.stdout {
+    color: #D5DBFE;
+}

crates/lanspread-tauri-deno-ts/src/App.tsx

@@ -1,6 +1,7 @@
 import { useCallback, useEffect, useRef, useState } from 'react';
 import { invoke } from '@tauri-apps/api/core';
 import { listen } from '@tauri-apps/api/event';
+import { WebviewWindow } from '@tauri-apps/api/webviewWindow';
 import { open } from '@tauri-apps/plugin-dialog';
 import { load } from '@tauri-apps/plugin-store';
 
@@ -71,6 +72,17 @@ interface GamesListPayload {
     active_operations?: ActiveOperation[];
 }
 
+interface UnpackLogEntry {
+    archive: string;
+    destination: string;
+    status_code: number | null;
+    stdout: string;
+    stderr: string;
+    started_at_ms: number;
+    finished_at_ms: number;
+    success: boolean;
+}
+
 interface GameThumbnailProps {
     gameId: string;
     alt: string;
@@ -151,6 +163,72 @@ const normalizeGamesListPayload = (payload: GamesListPayload | Game[]): GamesLis
     return payload;
 };
 
+const isUnpackLogsView = (): boolean => {
+    return new URLSearchParams(window.location.search).get('view') === 'unpack-logs';
+};
+
+const formatLogTime = (timestampMs: number): string => {
+    if (timestampMs <= 0) {
+        return 'unknown time';
+    }
+    return new Date(timestampMs).toLocaleString();
+};
+
+const UnpackLogsWindow = () => {
+    const [logs, setLogs] = useState<UnpackLogEntry[]>([]);
+
+    const refreshLogs = useCallback(async () => {
+        const unpackLogs = await invoke<UnpackLogEntry[]>('get_unpack_logs');
+        setLogs(unpackLogs);
+    }, []);
+
+    useEffect(() => {
+        let unlisten: (() => void) | undefined;
+
+        const setup = async () => {
+            await refreshLogs();
+            unlisten = await listen('unpack-logs-updated', () => {
+                void refreshLogs();
+            });
+        };
+
+        void setup();
+
+        return () => {
+            unlisten?.();
+        };
+    }, [refreshLogs]);
+
+    return (
+        <main className="unpack-log-window">
+            <div className="unpack-log-header">
+                <h1>Unpack Logs</h1>
+                <button className="settings-button" onClick={() => void refreshLogs()}>Refresh</button>
+            </div>
+            <div className="unpack-log-textfield" role="textbox" aria-readonly="true" tabIndex={0}>
+                {logs.length === 0 ? (
+                    <div className="unpack-log-empty">No unpack logs recorded yet.</div>
+                ) : logs.map((entry, index) => (
+                    <section className="unpack-log-entry" key={`${entry.finished_at_ms}-${index}`}>
+                        <div className={`unpack-log-meta ${entry.success ? 'success' : 'error'}`}>
+                            [{formatLogTime(entry.finished_at_ms)}] {entry.success ? 'OK' : 'FAILED'}
+                            {' '}status={entry.status_code ?? 'none'}
+                        </div>
+                        <div className="unpack-log-path">archive: {entry.archive}</div>
+                        <div className="unpack-log-path">dest: {entry.destination}</div>
+                        <pre className="unpack-log-stream stdout">
+                            {entry.stdout.trim() ? entry.stdout : '(stdout empty)'}
+                        </pre>
+                        {entry.stderr.trim() && (
+                            <pre className="unpack-log-stream stderr">{entry.stderr}</pre>
+                        )}
+                    </section>
+                ))}
+            </div>
+        </main>
+    );
+};
+
 const mergeGameUpdate = (
     game: Game,
     previous?: Game,
@@ -187,7 +265,7 @@ const mergeGameUpdate = (
     };
 };
 
-const App = () => {
+const MainWindow = () => {
     const [gameItems, setGameItems] = useState<Game[]>([]);
     const [searchTerm, setSearchTerm] = useState('');
     const [gameDir, setGameDir] = useState('');
@@ -733,6 +811,29 @@ const App = () => {
         }
     };
 
+    const openUnpackLogsWindow = async () => {
+        try {
+            const existing = await WebviewWindow.getByLabel('unpack-logs');
+            if (existing) {
+                await existing.setFocus();
+                return;
+            }
+
+            const logWindow = new WebviewWindow('unpack-logs', {
+                url: '/?view=unpack-logs',
+                title: 'Unpack Logs',
+                width: 900,
+                height: 700,
+                resizable: true,
+            });
+            await logWindow.once<unknown>('tauri://error', (event) => {
+                console.error('Error opening unpack logs window:', event.payload);
+            });
+        } catch (error) {
+            console.error('Error opening unpack logs window:', error);
+        }
+    };
+
     return (
         <main className="container">
             <div className="fixed-header">
@@ -781,10 +882,11 @@ const App = () => {
                                     className="search-input"
                                 />
                             </div>
-                            <div className="settings-container">
-                                <button onClick={dialogGameDir} className="settings-button">Set Game Directory</button>
-                                <span className="settings-text">{gameDir}</span>
-                            </div>
+	                        <div className="settings-container">
+	                            <button onClick={() => void openUnpackLogsWindow()} className="settings-button">Unpack Logs</button>
+	                            <button onClick={dialogGameDir} className="settings-button">Set Game Directory</button>
+	                            <span className="settings-text">{gameDir}</span>
+	                        </div>
                         </div>
                     </div>
                     ) : (
@@ -878,4 +980,8 @@ const App = () => {
     );
 };
 
+const App = () => {
+    return isUnpackLogsView() ? <UnpackLogsWindow /> : <MainWindow />;
+};
+
 export default App;