P3: depreciation straight-line by days through the final month, schedules by day (defects 22, 9, D-37)

The final month takes what the months before leave, spread over its days;
a disposed asset stops on its disposal day. A skipped month is caught up
in the month the run is made; a reversed run un-posts its month. New
schedules spread by day; equal-months schedules must start on the 1st.
Amounts round to the currency's own minor unit. Kani and Lean proofs; an
exhaustive search over runs, reversals and disposals.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01T3gXMVt7XJPi6ens1or9Dj

crates/ledger-mcp/handbook/fixed-assets.md

@@ -2,6 +2,7 @@
 
 - Register with books.register_asset, inspect with books.asset_schedule and books.list_assets, post monthly depreciation with books.run_depreciation (exempt from the receipt policy; the schedule is the evidence), and dispose with books.dispose_asset (preview first; the bill of sale is the receipt).
 - Depreciation is straight-line, book basis only; tax depreciation stays with the CPA.
+- It accrues by the day: a partial first month, the final month and a disposal month are prorated by days (the disposal day is held), and the lifetime total is exactly cost minus salvage. A month skipped is caught up by the next run (books.run_depreciation says how much under caught_up; a material miss is a restatement for the CPA); a disposal dated inside a month already run credits the extra days back; one dated before a later month's run is refused until that run is reversed.
 - Every asset gets a tag for the label on the thing itself (books.register_asset generates the next one, like FA-0001, unless the human has their own); record the manufacturer's serial number too, change either with books.label_asset, and print label sheets with books.asset_labels (give the human the PDF; print at 100% on Avery 5160/8160). Asset tools take the tag in place of the id.
 - Record every asset's federal tax basis beside its book value (books.set_asset_tax_basis, or tax_basis_rule on books.register_asset): cost for a purchase; for a member's contribution, the member's adjusted basis (what they paid, less depreciation they took) with rule personal_use_conversion (their personal property: tax basis is the lesser of value and their basis) or carryover (their business property). Book value stays fair market value.
 - books.export fixed_asset_register is the register for the CPA; books.show asset opens one in the viewer.

crates/ledger-mcp/handbook/prepaid-and-recurring.md

@@ -1,4 +1,5 @@
 # Prepaid expenses, deferred revenue and recurring entries
 
 - Prepaid expenses and deferred revenue: record the original payment (with its receipt), then books.create_schedule; books.run_schedules posts the monthly amortization (preview first; exempt from the receipt policy like depreciation).
+- A new schedule spreads by the day from its start (the [books] schedule_convention setting, default daily): a policy starting mid-month posts a small first and last month, so 12 months from March 15 is 13 month ends. Equal months (monthly_even) start on the 1st, so revenue is never earned early. Schedules from before keep their equal months.
 - Recurring entries (books.create_recurring, books.run_recurring) only ever create drafts: attach each actual receipt and post through the normal preview.