fix(core): preserve letter suffix case in normalizePhaseName (#1963)

* fix(core): preserve letter suffix case in normalizePhaseName (#1962)

normalizePhaseName uppercased letter suffixes (e.g., "16c" → "16C"),
causing directory/roadmap mismatches on case-sensitive filesystems.
init progress couldn't match directory "16C-name" to roadmap "16c".

Preserve original case — comparePhaseNum still uppercases for sorting
(correct), but normalizePhaseName is used for display and directory
creation where case must match the roadmap.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

* test(phase): update existing test to expect preserved letter case

The 'uppercases letters' test asserted the old behavior (3a → 03A).
With normalizePhaseName now preserving case, update expectations to
match (3a → 03a) and rename the test to 'preserves letter case'.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

---------

Co-authored-by: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

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

@@ -900,7 +900,10 @@ function normalizePhaseName(phase) {
   const match = stripped.match(/^(\d+)([A-Z])?((?:\.\d+)*)/i);
   if (match) {
     const padded = match[1].padStart(2, '0');
-    const letter = match[2] ? match[2].toUpperCase() : '';
+    // Preserve original case of letter suffix (#1962).
+    // Uppercasing causes directory/roadmap mismatches on case-sensitive filesystems
+    // (e.g., "16c" in ROADMAP.md → directory "16C-name" → progress can't match).
+    const letter = match[2] || '';
     const decimal = match[3] || '';
     return padded + letter + decimal;
   }

tests/bug-1962-phase-suffix-case.test.cjs

@@ -0,0 +1,49 @@
+/**
+ * Regression tests for bug #1962
+ *
+ * normalizePhaseName must preserve the original case of letter suffixes.
+ * Uppercasing "16c" to "16C" causes directory/roadmap mismatches on
+ * case-sensitive filesystems — init progress can't match the directory
+ * back to the roadmap phase entry.
+ */
+
+'use strict';
+
+const { describe, test } = require('node:test');
+const assert = require('node:assert/strict');
+
+const { normalizePhaseName } = require('../get-shit-done/bin/lib/core.cjs');
+
+describe('bug #1962: normalizePhaseName preserves letter suffix case', () => {
+  test('lowercase suffix preserved: 16c → 16c', () => {
+    assert.equal(normalizePhaseName('16c'), '16c');
+  });
+
+  test('uppercase suffix preserved: 16C → 16C', () => {
+    assert.equal(normalizePhaseName('16C'), '16C');
+  });
+
+  test('single digit padded with lowercase suffix: 1a → 01a', () => {
+    assert.equal(normalizePhaseName('1a'), '01a');
+  });
+
+  test('single digit padded with uppercase suffix: 1A → 01A', () => {
+    assert.equal(normalizePhaseName('1A'), '01A');
+  });
+
+  test('no suffix unchanged: 16 → 16', () => {
+    assert.equal(normalizePhaseName('16'), '16');
+  });
+
+  test('decimal suffix preserved: 16.1 → 16.1', () => {
+    assert.equal(normalizePhaseName('16.1'), '16.1');
+  });
+
+  test('letter + decimal preserved: 16c.2 → 16c.2', () => {
+    assert.equal(normalizePhaseName('16c.2'), '16c.2');
+  });
+
+  test('project code prefix stripped, suffix case preserved: CK-01a → 01a', () => {
+    assert.equal(normalizePhaseName('CK-01a'), '01a');
+  });
+});

tests/phase.test.cjs

@@ -1906,9 +1906,9 @@ describe('normalizePhaseName', () => {
     assert.strictEqual(normalizePhaseName('12A.2'), '12A.2');
   });
 
-  test('uppercases letters', () => {
-    assert.strictEqual(normalizePhaseName('3a'), '03A');
-    assert.strictEqual(normalizePhaseName('12b.1'), '12B.1');
+  test('preserves letter case', () => {
+    assert.strictEqual(normalizePhaseName('3a'), '03a');
+    assert.strictEqual(normalizePhaseName('12b.1'), '12b.1');
   });
 
   test('handles multi-level decimal phases', () => {