feat: version display + issues board

Version: CalVer + git hash shown in top-right corner of main page.
Built via Docker ARG BUILD_VERSION at build time. Served via /api-version.

Issues Board: shared notepad window for tracking issues with plugin,
overlord, nav files, macros. Stored in openissues.json on server.
- GET/POST/DELETE /issues endpoints
- Draggable window matching Chat/Radar pattern
- Category tags (plugin, overlord, nav, macro, other) with colors
- Add/resolve issues through the UI

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

static/style.css

@@ -525,7 +525,7 @@ body {
   margin-top: 4px;
 }
 
-.chat-window, .stats-window, .inventory-window, .character-window, .radar-window {
+.chat-window, .stats-window, .inventory-window, .character-window, .radar-window, .issues-window {
   position: absolute;
   top: 10px;
   /* position window to start just right of the sidebar */
@@ -2643,3 +2643,64 @@ table.ts-allegiance td:first-child {
 .radar-btn:hover {
   background: #664499;
 }
+
+/* ─── Issues Board ─── */
+
+.issues-window {
+  width: 500px;
+  height: 450px;
+}
+
+.issues-window .window-content {
+  display: flex;
+  flex-direction: column;
+  overflow: hidden;
+}
+
+.issues-list {
+  flex: 1;
+  overflow-y: auto;
+  min-height: 0;
+  padding: 4px;
+}
+
+.issue-row {
+  padding: 6px 8px;
+  border-bottom: 1px solid #333;
+}
+
+.issue-row:hover {
+  background: #1a1a2a;
+}
+
+.issue-category {
+  display: inline-block;
+  padding: 1px 6px;
+  border-radius: 3px;
+  color: #fff;
+  font-size: 0.65rem;
+  font-weight: bold;
+  text-transform: uppercase;
+}
+
+.issue-resolve-btn {
+  padding: 1px 6px;
+  font-size: 0.65rem;
+  background: transparent;
+  color: #4a4;
+  border: 1px solid #4a4;
+  cursor: pointer;
+  border-radius: 3px;
+  margin-left: 8px;
+}
+
+.issue-resolve-btn:hover {
+  background: #4a4;
+  color: #fff;
+}
+
+.issues-form {
+  padding: 6px 8px;
+  border-top: 1px solid #444;
+  background: #1a1a1a;
+}