A post's allocation rule becomes a dated series: a version takes effect in its
month and continues until the next replaces it. Per-month overrides survive
alongside as one-month exceptions, because collapsing the two loses the
distinction between a permanent change and a temporary one.
A post with no version yet allocates zero rather than applying its earliest
rule backwards, which would invent budget for months never budgeted and let
the rollover fold carry that fiction forward.
Requires the project's first real migration (schemaVersion 1 -> 2). It is a
pure shape change and behaviour-preserving by construction, and the spec makes
that a tested property rather than an assumption: every month's allocation must
be identical before and after.
Co-Authored-By: Claude Opus 5 (1M context) <[email protected]>
Three entry-form changes specified together because they share the same tab
order: keyboard-driven bulk rows, purchases that no longer demand a day, and
an optional note per purchase.
Records why the date change widens IsoDate rather than splitting it into
month + optional day: the split is the better model but changes a type every
layer depends on and needs a migration run in the browser against the user's
only copy of their data, for an identical user-visible outcome. Verified that
monthOf() already parses both date shapes and still rejects out-of-range
months.
Time-versioned allocation rules are explicitly out of scope and get their own
cycle.
Co-Authored-By: Claude Opus 5 (1M context) <[email protected]>
Design for a personal budgeting PWA replacing a spreadsheet workflow.
Key decisions captured:
- Static SPA, no backend in the data path, so it deploys to both GitHub
Pages and a self-hosted Docker image from one build artifact
- Bun toolchain (bun init --react=shadcn); no Vite, no Electron
- Pure derivation core over an IndexedDB fact store; envelope rollover
makes caching worthless, so every figure is folded from raw facts
- One Purchase entity covers simple, split, and financed purchases, which
is what lets splits and finance plans compose without special-casing
- Money is a float, with mandatory rounding at boundaries and last-part-
by-subtraction so distributed parts sum exactly to the whole
Co-Authored-By: Claude Opus 5 (1M context) <[email protected]>
