beacon: add collapsible completed projects + export/import save files

- Completed research projects are now collapsed by default (click to expand),
  preventing panel clutter in mid/late game. Toggle state persists in saves.
- Export saves as JSON files with E key or Export button
- Import saves from file with I key or Import button (validates before loading)
- Ctrl+S keyboard shortcut for quick save
- Updated keybind hints in startup log

game.js

@@ -1729,13 +1729,21 @@ function renderProjects() {
 
     let html = '';
 
-    // Show completed projects
-    if (G.completedProjects) {
-        for (const id of G.completedProjects) {
-            const pDef = PDEFS.find(p => p.id === id);
-            if (pDef) {
-                html += `<div class="project-done">OK ${pDef.name}</div>`;
+    // Collapsible completed projects section
+    if (G.completedProjects && G.completedProjects.length > 0) {
+        const count = G.completedProjects.length;
+        const collapsed = G.projectsCollapsed !== false;
+        html += `<div id="completed-header" onclick="toggleCompletedProjects()" style="cursor:pointer;font-size:9px;color:#555;padding:4px 0;border-bottom:1px solid #1a2a1a;margin-bottom:4px;user-select:none">`;
+        html += `${collapsed ? '▶' : '▼'} COMPLETED (${count})</div>`;
+        if (!collapsed) {
+            html += `<div id="completed-list">`;
+            for (const id of G.completedProjects) {
+                const pDef = PDEFS.find(p => p.id === id);
+                if (pDef) {
+                    html += `<div class="project-done">OK ${pDef.name}</div>`;
+                }
             }
+            html += `</div>`;
         }
     }
 
@@ -1759,6 +1767,11 @@ function renderProjects() {
     container.innerHTML = html;
 }
 
+function toggleCompletedProjects() {
+    G.projectsCollapsed = G.projectsCollapsed === false ? true : false;
+    renderProjects();
+}
+
 function renderStats() {
     const set = (id, v, raw) => {
         const el = document.getElementById(id);
@@ -2080,6 +2093,49 @@ function dismissOfflinePopup() {
     if (el) el.style.display = 'none';
 }
 
+// === EXPORT / IMPORT SAVE FILES ===
+function exportSave() {
+    const raw = localStorage.getItem('the-beacon-v2');
+    if (!raw) { log('No save data to export.'); return; }
+    const blob = new Blob([raw], { type: 'application/json' });
+    const url = URL.createObjectURL(blob);
+    const a = document.createElement('a');
+    a.href = url;
+    const ts = new Date().toISOString().slice(0, 10);
+    a.download = `beacon-save-${ts}.json`;
+    a.click();
+    URL.revokeObjectURL(url);
+    log('Save exported to file.');
+}
+
+function importSave() {
+    const input = document.createElement('input');
+    input.type = 'file';
+    input.accept = '.json,application/json';
+    input.onchange = function(e) {
+        const file = e.target.files[0];
+        if (!file) return;
+        const reader = new FileReader();
+        reader.onload = function(ev) {
+            try {
+                const data = JSON.parse(ev.target.result);
+                if (!data.code && !data.totalCode && !data.buildings) {
+                    log('Import failed: file does not look like a Beacon save.');
+                    return;
+                }
+                if (confirm('Import this save? Current progress will be overwritten.')) {
+                    localStorage.setItem('the-beacon-v2', ev.target.result);
+                    location.reload();
+                }
+            } catch (err) {
+                log('Import failed: invalid JSON file.');
+            }
+        };
+        reader.readAsText(file);
+    };
+    input.click();
+}
+
 // === SAVE / LOAD ===
 function showSaveToast() {
     const el = document.getElementById('save-toast');
@@ -2124,6 +2180,7 @@ function saveGame() {
         sprintActive: G.sprintActive || false,
         sprintTimer: G.sprintTimer || 0,
         sprintCooldown: G.sprintCooldown || 0,
+        projectsCollapsed: G.projectsCollapsed !== false,
         savedAt: Date.now()
     };
 
@@ -2260,7 +2317,7 @@ function initGame() {
     log('Click WRITE CODE or press SPACE to start.');
     log('Build AutoCode for passive production.');
     log('Watch for Research Projects to appear.');
-    log('Keys: SPACE=Code S=Code Sprint 1=Ops->Code 2=Ops->Compute 3=Ops->Knowledge 4=Ops->Trust B=Buy x1/x10/MAX');
+    log('Keys: SPACE=Code S=Sprint 1-4=Ops B=Buy x1/10/MAX E=Export I=Import Ctrl+S=Save');
 }
 
 window.addEventListener('load', function () {
@@ -2308,4 +2365,14 @@ window.addEventListener('keydown', function (e) {
         else setBuyAmount(1);
     }
     if (e.code === 'KeyS') activateSprint();
+    if (e.code === 'KeyE') exportSave();
+    if (e.code === 'KeyI') importSave();
+});
+
+// Ctrl+S to save (must be on keydown to preventDefault)
+window.addEventListener('keydown', function (e) {
+    if ((e.ctrlKey || e.metaKey) && e.code === 'KeyS') {
+        e.preventDefault();
+        saveGame();
+    }
 });

index.html

@@ -130,7 +130,11 @@ body{background:var(--bg);color:var(--text);font-family:'SF Mono','Cascadia Code
 <div id="sprint-label" style="font-size:9px;color:#666;margin-top:2px;text-align:center"></div>
 </div>
 <div id="alignment-ui" style="display:none"></div>
-<button class="save-btn" onclick="saveGame()">Save Game</button>
+<button class="save-btn" onclick="saveGame()">Save Game [Ctrl+S]</button>
+<div style="display:flex;gap:4px;margin-top:4px">
+<button class="save-btn" onclick="exportSave()" style="flex:1">Export [E]</button>
+<button class="save-btn" onclick="importSave()" style="flex:1">Import [I]</button>
+</div>
 <button class="reset-btn" onclick="if(confirm('Reset all progress?')){localStorage.removeItem('the-beacon-v2');location.reload()}">Reset Progress</button>
 <h2>BUILDINGS</h2>
 <div id="buildings"></div>