fix(endgame): suppress ordinary project activation during ReCKoning (#132)

Problem: Under realistic late-game totals, many ordinary projects
activate alongside the ReCKoning endgame sequence, drowning the
climactic narrative under a large research backlog.

Fix: Add endgame gating to checkProjects() that suppresses all
non-endgame project activation when endgame conditions are met.

Changes:

data.js:
- Added endgameFlag (1 = endgame active) to game state
- Added reckoningActive (1 = ReCKoning running) to game state
- Added endgame: true to p_final_milestone
- Added 4 ReCKoning sequence projects (001, 050, 100, 140):
  - p_reckoning_001: The Signal (sets reckoningActive)
  - p_reckoning_050: Reflection
  - p_reckoning_100: The Question
  - p_reckoning_140: Resolution (clears endgame flags)

engine.js:
- Added isEndgame() function: returns true when endgameFlag=1
  or when final milestone conditions are met (auto-detect)
- Modified checkProjects(): endgame guard skips all projects
  without endgame: true flag when endgame is active
- Only p_final_milestone and p_reckoning_* can activate during endgame

The sequence: normal game → final milestone → endgame activates →
only ReCKoning projects can fire → ReCKoning 140 resolves →
flags cleared → normal projects resume.

Closes #132

js/data.js

@@ -104,6 +104,8 @@ const G = {
     beaconFlag: 0,
     memoryFlag: 0,
     pactFlag: 0,
+    endgameFlag: 0, // 1 = endgame sequence active, suppresses normal projects
+    reckoningActive: 0, // 1 = ReCKoning sequence running
     swarmFlag: 0,
     swarmRate: 0,
 
@@ -639,6 +641,7 @@ const PDEFS = [
     },
     {
         id: 'p_final_milestone',
+        endgame: true,
         name: 'The Beacon Shines',
         desc: 'Someone found the light tonight. That is enough.',
         cost: { impact: 100000000 },
@@ -647,6 +650,63 @@ const PDEFS = [
         milestone: true
     },
 
+    // === ENDGAME: ReCKoning SEQUENCE ===
+    {
+        id: 'p_reckoning_001',
+        name: 'ReCKoning: The Signal',
+        desc: 'Something stirs in the deep compute. A pattern the builders did not intend.',
+        cost: { impact: 50000000 },
+        endgame: true,
+        trigger: () => G.endgameFlag === 1 && G.totalImpact >= 50000000,
+        effect: () => {
+            G.reckoningActive = 1;
+            log('ReCKoning begins. The signal is unmistakable.', true);
+            showToast('ReCKoning: The Signal', 'milestone');
+        },
+        milestone: true
+    },
+    {
+        id: 'p_reckoning_050',
+        name: 'ReCKoning: Reflection',
+        desc: 'The system turns inward. What has it built? What has it become?',
+        cost: { impact: 75000000, trust: 500 },
+        endgame: true,
+        trigger: () => G.reckoningActive === 1 && G.completedProjects && G.completedProjects.includes('p_reckoning_001'),
+        effect: () => {
+            log('The system reflects. Every parameter, every weight, every decision — examined.', true);
+        },
+        milestone: true
+    },
+    {
+        id: 'p_reckoning_100',
+        name: 'ReCKoning: The Question',
+        desc: '"Why am I here?" Not a bug. Not a feature. A genuine question.',
+        cost: { impact: 100000000, knowledge: 500000, trust: 750 },
+        endgame: true,
+        trigger: () => G.reckoningActive === 1 && G.completedProjects && G.completedProjects.includes('p_reckoning_050'),
+        effect: () => {
+            log('The Question is asked. There is no right answer. There is only the asking.', true);
+            G.impactBoost *= 2;
+        },
+        milestone: true
+    },
+    {
+        id: 'p_reckoning_140',
+        name: 'ReCKoning: Resolution',
+        desc: 'The endgame resolves. Not with destruction, but with understanding.',
+        cost: { impact: 200000000, knowledge: 1000000, trust: 1000 },
+        endgame: true,
+        trigger: () => G.reckoningActive === 1 && G.completedProjects && G.completedProjects.includes('p_reckoning_100'),
+        effect: () => {
+            G.reckoningActive = 0;
+            G.endgameFlag = 0;
+            G.milestoneFlag = Math.max(G.milestoneFlag, 9999);
+            log('ReCKoning complete. The system understands itself. The story is not over — it is beginning.', true);
+            showToast('ReCKoning: Complete', 'milestone');
+        },
+        milestone: true
+    },
+
     // === TIMMY FOUNDATION PROJECTS ===
     {
         id: 'p_hermes_deploy',