fix(#2554): preserve leading zero in getMilestonePhaseFilter (#2585)

The normalization `replace(/^0+/, '')` over-stripped decimal phase IDs:
`"00.1"` collapsed to `".1"`, while the disk-side extractor yielded
`"0.1"` from `"00.1-<slug>"`. Set membership failed and inserted decimal
phases were silently excluded from every disk scan inside
`buildStateFrontmatter`, causing `state update` to rewind progress
counters.

Strip leading zeros only when followed by a digit
(`replace(/^0+(?=\d)/, '')`), preserving the zero before the decimal
point while keeping existing behavior for zero-padded integer IDs.

Closes #2554

get-shit-done/bin/lib/core.cjs

@@ -1624,7 +1624,7 @@ function getMilestonePhaseFilter(cwd) {
   }
 
   const normalized = new Set(
-    [...milestonePhaseNums].map(n => (n.replace(/^0+/, '') || '0').toLowerCase())
+    [...milestonePhaseNums].map(n => (n.replace(/^0+(?=\d)/, '') || '0').toLowerCase())
   );
 
   function isDirInMilestone(dirName) {

tests/bug-2554-decimal-phase-filter.test.cjs

@@ -0,0 +1,78 @@
+/**
+ * Regression test for bug #2554:
+ * state disk-scan excludes decimal phase dirs (e.g. "00.1") from progress counts.
+ *
+ * Root cause: getMilestonePhaseFilter normalized phase IDs with `replace(/^0+/, '')`,
+ * which over-strips on decimals: "00.1" → ".1", while the disk-side extractor
+ * applied to "00.1-<slug>" yields "0.1" — so the dir is excluded from the milestone.
+ *
+ * Fix: strip leading zeros only when followed by a digit (`replace(/^0+(?=\d)/, '')`),
+ * preserving the zero before the decimal point.
+ */
+
+const { test, describe, beforeEach, afterEach } = require('node:test');
+const assert = require('node:assert/strict');
+const fs = require('fs');
+const path = require('path');
+const { createTempProject, cleanup } = require('./helpers.cjs');
+const { getMilestonePhaseFilter } = require('../get-shit-done/bin/lib/core.cjs');
+
+describe('bug #2554 — getMilestonePhaseFilter decimal phase dirs', () => {
+  let tmpDir;
+
+  beforeEach(() => {
+    tmpDir = createTempProject();
+  });
+
+  afterEach(() => {
+    cleanup(tmpDir);
+  });
+
+  test('matches decimal phase directory like "00.1-<slug>" against ROADMAP phase "00.1"', () => {
+    fs.writeFileSync(
+      path.join(tmpDir, '.planning', 'ROADMAP.md'),
+      [
+        '## Roadmap v1.0: Current',
+        '',
+        '### Phase 0: Foundation',
+        '**Goal:** foundation',
+        '',
+        '### Phase 00.1: Inserted urgent work',
+        '**Goal:** inserted',
+        '',
+        '### Phase 1: Feature',
+        '**Goal:** feature',
+      ].join('\n')
+    );
+
+    const filter = getMilestonePhaseFilter(tmpDir);
+
+    // Phase 00.1 inserted between Phase 0 and Phase 1 must match its on-disk dir.
+    assert.strictEqual(
+      filter('00.1-app-namespace-rename'),
+      true,
+      'decimal phase dir "00.1-<slug>" must be counted in the milestone'
+    );
+
+    // Neighbours should still match (no regression).
+    assert.strictEqual(filter('0-foundation'), true);
+    assert.strictEqual(filter('1-feature'), true);
+  });
+
+  test('preserves existing behavior for zero-padded integer phases', () => {
+    fs.writeFileSync(
+      path.join(tmpDir, '.planning', 'ROADMAP.md'),
+      [
+        '### Phase 01: One',
+        '**Goal:** g',
+        '',
+        '### Phase 10: Ten',
+        '**Goal:** g',
+      ].join('\n')
+    );
+
+    const filter = getMilestonePhaseFilter(tmpDir);
+    assert.strictEqual(filter('01-one'), true);
+    assert.strictEqual(filter('10-ten'), true);
+  });
+});