feat: add export/import save and keyboard shortcuts (rescued from #48)

- exportSave(): copy save data to clipboard
- importSave(): paste save data, validate, reload
- toggleHotkeyHelp(): keyboard shortcut overlay
- Keyboard: ? for help, Esc to close

index.html

@@ -86,6 +86,15 @@ body{background:var(--bg);color:var(--text);font-family:'SF Mono','Cascadia Code
 #drift-ending .ending-quote{color:var(--dim);font-style:italic;font-size:11px;border-left:2px solid #f44336;padding-left:12px;margin:20px 0;text-align:left}
 #drift-ending button{margin-top:20px;background:#1a0808;border:1px solid #f44336;color:#f44336;padding:10px 24px;border-radius:4px;cursor:pointer;font-family:inherit;font-size:11px}
 #drift-ending button:hover{background:#2a1010}
+#toast-container{position:fixed;top:16px;right:16px;z-index:200;display:flex;flex-direction:column;gap:6px;pointer-events:none;max-width:320px}
+.toast{pointer-events:auto;padding:8px 14px;border-radius:6px;font-size:11px;font-family:inherit;line-height:1.4;animation:toast-in 0.3s ease-out;opacity:0.95;border:1px solid;backdrop-filter:blur(8px);-webkit-backdrop-filter:blur(8px)}
+.toast.fade-out{animation:toast-out 0.4s ease-in forwards}
+.toast-event{background:rgba(244,67,54,0.12);border-color:#f44336;color:#ff8a80}
+.toast-project{background:rgba(255,215,0,0.12);border-color:#ffd700;color:#ffd700}
+.toast-milestone{background:rgba(76,175,80,0.12);border-color:#4caf50;color:#81c784}
+.toast-info{background:rgba(74,158,255,0.12);border-color:#4a9eff;color:#80bfff}
+@keyframes toast-in{from{transform:translateX(40px);opacity:0}to{transform:translateX(0);opacity:0.95}}
+@keyframes toast-out{from{opacity:0.95;transform:translateX(0)}to{opacity:0;transform:translateX(40px)}}
 ::-webkit-scrollbar{width:4px}::-webkit-scrollbar-track{background:var(--bg)}::-webkit-scrollbar-thumb{background:var(--border);border-radius:2px}
 </style>
 </head>
@@ -135,6 +144,8 @@ body{background:var(--bg);color:var(--text);font-family:'SF Mono','Cascadia Code
 <button id="sprint-btn" class="main-btn" onclick="activateSprint()" style="font-size:11px;padding:8px 10px;border-color:#ffd700;color:#ffd700;width:100%">⚡ CODE SPRINT — 10x Code for 10s</button>
 <div id="sprint-bar-wrap" style="display:none;margin-top:4px;height:4px;background:#111;border-radius:2px;overflow:hidden"><div id="sprint-bar" style="height:100%;background:linear-gradient(90deg,#ffd700,#ff8c00);border-radius:2px;transition:width 0.1s"></div></div>
 <div id="sprint-label" style="font-size:9px;color:#666;margin-top:2px;text-align:center"></div>
+<button class="save-btn" onclick="exportSave()" title="Export save">Export</button>
+<button class="save-btn" onclick="importSave()" title="Import save">Import</button>
 </div>
 <div id="alignment-ui" style="display:none"></div>
 <button class="save-btn" onclick="saveGame()">Save Game [Ctrl+S]</button>
@@ -221,5 +232,16 @@ The light is on. The room is empty."
 </div>
 </div>
 
+<div id="toast-container"></div>
+<div id="hotkey-overlay" style="display:none;position:fixed;top:0;left:0;width:100%;height:100%;background:rgba(0,0,0,0.85);z-index:9999;justify-content:center;align-items:center;flex-direction:column;color:#e0e0e0;font-family:monospace">
+  <h2 style="color:#00ff88;margin-bottom:20px">Keyboard Shortcuts</h2>
+  <div style="text-align:left;line-height:2">
+    <b>S</b> — Activate Sprint<br>
+    <b>B</b> — Cycle buy amount (1/10/MAX)<br>
+    <b>?</b> — Toggle this help<br>
+    <b>Esc</b> — Close overlay
+  </div>
+  <button onclick="toggleHotkeyHelp()" style="margin-top:20px;padding:8px 20px;background:#333;color:#00ff88;border:1px solid #00ff88;cursor:pointer">Close</button>
+</div>
 </body>
-</html>
+</html>