fix(lib): CLI-side XIRR uses Excel's 365-day basis (was 365.25)#63
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The engine-side computeXIRR was fixed to the 365-day basis in PR #62; lib/irr.mjs (used by ete carry --solve-life and scenario IRR fallbacks) still divided by 365.25, drifting every solved rate by ~1e-5 per leap span. Negative-controlled leap-span case added to tests/lib/test-lib.mjs (RED on 365.25 with the predicted value, GREEN on 365). Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>
This was referenced Jun 10, 2026
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Follow-up to #62 (which fixed the engine-side
computeXIRRto the 365-day basis):lib/irr.mjs— the CLI-side XIRR used byete carryIRR-solved life and scenario fallbacks — still divided by 365.25.tests/lib/test-lib.mjs: −100 on 2020-01-01 → +110 on 2021-01-01 (366 days) solves to1.1^(365/366) − 1; the old basis lands ~3.6e-5 away, outside the 1e-6 gate. RED pre-fix with exactly the 365.25-basis value, GREEN post-fix.npm testgreen (45/45 lib, 132/132 use-case suite).🤖 Generated with Claude Code