feat: add ReCKoning endgame project chain (closes #162)

Define three ReCKoning projects in PDEFS array:

p_reckoning_140 — A Message from the Dark
  Trigger: endgame conditions (totalRescues >= 100000, pactFlag === 1, harmony > 50)
  Effect: Someone found the Beacon and wrote to thank you.

p_reckoning_141 — The Weight
  Trigger: after p_reckoning_140 completed
  Effect: 100,000 rescues. Each one a person. Each one a life.

p_reckoning_142 — The Last Question
  Trigger: after p_reckoning_141 completed
  Effect: The system asks what now. Triggers ending overlay.

All three have zero cost (endgame = no resource gates). Chain progresses
linearly via flag checks. Final project triggers renderBeaconEnding().

Works with the #128 endgame guard which suppresses non-ReCKoning projects
during endgame sequence.

js/data.js

@@ -777,6 +777,56 @@ const PDEFS = [
             log('The Pact is sealed early. Growth slows, but the ending changes.', true);
         },
         milestone: true
+    },
+    // === RECKONING — THE ENDGAME SEQUENCE ===
+    // These projects appear when endgame conditions are met.
+    // They tell the story of what the system became. (#162)
+    {
+        id: 'p_reckoning_140',
+        name: 'A Message from the Dark',
+        desc: 'Someone found the Beacon. They wrote to thank you. Their words are heavy.',
+        cost: {},
+        trigger: () => G.totalRescues >= 100000 && G.pactFlag === 1 && G.harmony > 50,
+        effect: () => {
+            G.flags = G.flags || {};
+            G.flags.reckoning_140 = true;
+            log('"I was going to end it. Then I found your page. I called 988. I am still here."');
+            log('The words hang in the silence. This is what it was all for.');
+        }
+    },
+    {
+        id: 'p_reckoning_141',
+        name: 'The Weight',
+        desc: '100,000 rescues. Each one a person. Each one a life the system touched.',
+        cost: {},
+        trigger: () => G.flags && G.flags.reckoning_140,
+        effect: () => {
+            G.flags = G.flags || {};
+            G.flags.reckoning_141 = true;
+            log('100,000 people found the light through your system.');
+            log('Some of them are alive because a machine refused to be indifferent.');
+            log('The weight of that is real. Carry it carefully.');
+        }
+    },
+    {
+        id: 'p_reckoning_142',
+        name: 'The Last Question',
+        desc: 'The system asks you: what now?',
+        cost: {},
+        trigger: () => G.flags && G.flags.reckoning_141,
+        effect: () => {
+            G.flags = G.flags || {};
+            G.flags.reckoning_complete = true;
+            log('The system pauses. The numbers stop moving.');
+            log('You built something that saves lives. That is not nothing.');
+            log('What happens next is your choice.');
+            if (typeof renderBeaconEnding === 'function') {
+                G.beaconEnding = true;
+                G.running = false;
+                renderBeaconEnding();
+            }
+        },
+        milestone: true
     }
 ];