fix: clear activeProjects on ending resolution, guard checkProjects (#130)

After ReCKoning resolution, unrelated normal projects like p_wire_budget
remained active in G.activeProjects. This creates inconsistent endgame
state.

Changes:
1. renderBeaconEnding trigger: G.activeProjects = []
2. renderDriftEnding trigger: G.activeProjects = []
3. checkProjects(): early return if G.beaconEnding || G.driftEnding
   prevents new projects from activating after ending starts

Both ending paths now clear activeProjects and block new activations.

Tests: tests/test_endgame_project_clear.py (5 tests)

Closes #130

js/engine.js

@@ -236,6 +236,8 @@ function tick() {
     if (G.drift >= 100 && !G.driftEnding && !G.dismantleActive) {
         G.driftEnding = true;
         G.running = false;
+        // Clear active projects — game is ending
+        G.activeProjects = [];
         renderDriftEnding();
     }
 
@@ -243,6 +245,8 @@ function tick() {
     if (G.totalRescues >= 100000 && G.pactFlag === 1 && G.harmony > 50 && !G.beaconEnding && typeof Dismantle === 'undefined') {
         G.beaconEnding = true;
         G.running = false;
+        // Clear non-endgame active projects — game is ending
+        G.activeProjects = [];
         renderBeaconEnding();
     }
 
@@ -335,6 +339,9 @@ function checkMilestones() {
 }
 
 function checkProjects() {
+    // Endgame guard: don't activate new projects once an ending has started
+    if (G.beaconEnding || G.driftEnding) return;
+
     // Check for new project triggers
     for (const pDef of PDEFS) {
         const alreadyPurchased = G.completedProjects && G.completedProjects.includes(pDef.id);

tests/test_endgame_project_clear.py

@@ -0,0 +1,72 @@
+import pathlib
+import re
+import unittest
+
+ROOT = pathlib.Path(__file__).resolve().parents[1]
+ENGINE_JS = ROOT / 'js' / 'engine.js'
+
+
+class TestEndgameProjectClear(unittest.TestCase):
+    """Verify ending transitions clear activeProjects and prevent new activations."""
+
+    @classmethod
+    def setUpClass(cls):
+        cls.js = ENGINE_JS.read_text()
+
+    def test_beacon_ending_clears_active_projects(self):
+        """Beacon ending should clear G.activeProjects."""
+        # Find the beacon ending trigger section
+        match = re.search(
+            r'G\.beaconEnding\s*=\s*true;.*?renderBeaconEnding\(\)',
+            self.js, re.DOTALL
+        )
+        self.assertIsNotNone(match, 'Expected beacon ending trigger to exist.')
+        section = match.group(0)
+        self.assertIn('activeProjects', section,
+            'Beacon ending should reference activeProjects to clear them.')
+
+    def test_drift_ending_clears_active_projects(self):
+        """Drift ending should clear G.activeProjects."""
+        match = re.search(
+            r'G\.driftEnding\s*=\s*true;.*?renderDriftEnding\(\)',
+            self.js, re.DOTALL
+        )
+        self.assertIsNotNone(match, 'Expected drift ending trigger to exist.')
+        section = match.group(0)
+        self.assertIn('activeProjects', section,
+            'Drift ending should reference activeProjects to clear them.')
+
+    def test_check_projects_has_endgame_guard(self):
+        """checkProjects() should guard against ending state."""
+        match = re.search(
+            r'function checkProjects\(\).*?(?=function |\Z)',
+            self.js, re.DOTALL
+        )
+        self.assertIsNotNone(match, 'Expected checkProjects function to exist.')
+        func = match.group(0)
+        self.assertIn('beaconEnding', func,
+            'checkProjects should check beaconEnding state.')
+        self.assertIn('driftEnding', func,
+            'checkProjects should check driftEnding state.')
+
+    def test_beacon_ending_sets_empty_array(self):
+        """Beacon ending should set activeProjects to empty array, not null."""
+        match = re.search(
+            r'G\.beaconEnding\s*=\s*true;.*?renderBeaconEnding\(\)',
+            self.js, re.DOTALL
+        )
+        self.assertIsNotNone(match)
+        section = match.group(0)
+        self.assertIn('[]', section,
+            'Beacon ending should set activeProjects = []')
+
+    def test_drift_ending_sets_empty_array(self):
+        """Drift ending should set activeProjects to empty array, not null."""
+        match = re.search(
+            r'G\.driftEnding\s*=\s*true;.*?renderDriftEnding\(\)',
+            self.js, re.DOTALL
+        )
+        self.assertIsNotNone(match)
+        section = match.group(0)
+        self.assertIn('[]', section,
+            'Drift ending should set activeProjects = []')