fix(cpm): cap Late Finish at project duration so SS/FF/SF long-poles stay critical

analytics.js

@@ -169,7 +169,12 @@ export function computeCpm(tasks, opts = {}) {
           else if (l.type === 'SF') c = slf - l.lag + d;
           else c = sls - l.lag; // FS
           return Math.min(m, c);
-        }, Infinity)
+          // Seed with projectDurationDays (not Infinity): standard CPM caps every
+          // activity's Late Finish at project completion, then tightens it with
+          // successor constraints. With Infinity, a node whose only successor links
+          // are SS/FF/SF could take an LF looser than the project end, giving a
+          // truly-critical activity false total float (and an empty critical path).
+        }, projectDurationDays)
       : projectDurationDays;
     lf.set(id, finish);
     ls.set(id, finish - d);

package.json

@@ -17,7 +17,7 @@
     "fuzz": "node --test tests/fuzz/*.mjs"
   },
   "dependencies": {
-    "@hono/node-server": "^1.19.14",
+    "@hono/node-server": "^2.0.12",
     "hono": "^4.12.27"
   },
   "devDependencies": {

tests/unit/dep-types.test.mjs

@@ -61,4 +61,22 @@ const T = (id, duration, predecessors = '') => ({ id, duration, predecessors });
   assert.equal(r.cycleDetected, true);
 }
 
+// backward pass caps Late Finish at the project duration. An SS long-pole with a
+// short terminal follow-on: A (10d) alone drives the schedule end; B (2d) starts
+// with A but finishes early. A must be critical with zero total float. Regression:
+// seeding the successor reduce with Infinity left A's LF uncapped at 18 (> project
+// duration 10), giving A a false slack of 8, marking it non-critical, and returning
+// an EMPTY critical path for a schedule that plainly has one.
+{
+  const r = computeCpm([T('A', 10), T('B', 2, 'ASS')]);
+  assert.equal(r.projectDurationDays, 10, 'A(0-10) is the long pole');
+  assert.equal(r.perTask.A.lf, 10, 'LF capped at project duration, not 18');
+  assert.equal(r.perTask.A.slack, 0, 'sole long-pole activity has zero total float');
+  assert.ok(r.perTask.A.critical, 'A is critical');
+  assert.deepEqual(r.criticalPath, ['A'], 'critical path is A, not empty');
+  // B keeps its real slack and stays non-critical.
+  assert.equal(r.perTask.B.slack, 8, 'B(0-2) has 8d float to the project end');
+  assert.equal(r.perTask.B.critical, false);
+}
+
 console.log('✓ dependency-type (SS/FF/SF+lag) tests passed');