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