Separate instants from civil dates and add WAX-0034 Monetary Values and Currency

[RobGrafrath]

What this changes and why

A review of the record for assumptions that hold only in one currency and one time zone found two gaps in the Wax foundation. This pull request closes both before any code or event exists, when the fix costs nothing.

Dates. WAX-0012 said all date and time values are stored in UTC. That is right for moments but wrong for calendar dates such as a due date or a date of birth, which name a day and have no zone. The record already uses day-valued fields (HIVE-0001, HIVE-0003, HIVE-0005, and the date type in WAX-0022), and HIVE-0008's statement run takes a through date without saying which midnight it means. The first commit separates instants from civil dates, gives each organization a business zone, gives occurred_at and recorded_at precise meanings, names the business date fields, and makes due times and recurring jobs record how they were counted and in which zone.

Money. Amounts were bare numbers (the worked example in WAX-0001), and currency was defined once per installation (WAX-0007). The second commit adds WAX-0034 Monetary Values and Currency. Every monetary value becomes an exact decimal amount plus an ISO 4217 code. An installation whose Region Packs name one currency gets that currency as its default, applied automatically and stamped on every stored value, so single-currency installations never specify a currency. OpenAR code and certified modules always specify the currency in code and never rely on the default, and continuous integration runs in a configuration with more than one currency to enforce it.

Decisions the maintainer made for this change

• The money rules go in a new decision file, WAX-0034, not in a section of WAX-0001.
• The Region Pack and Language Pack tiers in WAX-0007 become "Yes (1+)", meaning at least one.
• The default currency is stamped on every stored value.
• OpenAR code and certified modules always specify the currency in code and never rely on the default.

Defaults chosen for review

These were recommended and are not yet explicitly confirmed, so they are the first things to check.

• occurred_at is asserted by the actor or source and may precede recorded_at (WAX-0001).
• The calendar and the date arithmetic service live in WAX-0012 and ship in v2.
• The hash input is not changed here. WAX-0001 says the event hash covers the full payload, while WAX-0013 lists specific fields and omits recorded_at, source, the correlation fields, and metadata. The two need reconciling before hash computation activates in v2, in a separate change.
• WAX-0034 enters as Proposed 0.1. Adoption to 1.0 is the Foundation's decision on merge.

Interacting decisions

WAX-0001, WAX-0007, WAX-0012, WAX-0013, WAX-0019, WAX-0022, WAX-0023, WAX-0026, WAX-0027, WAX-0028, and SHARED-0007 for the continuous integration baseline. No decision is contradicted. Follow-on edits to HIVE-0005, HIVE-0006, HIVE-0007, HIVE-0008, SHARED-0006, and MOD-PURCHASE-0001 (an account's denomination currency, civil posting dates, per-currency control totals) build on this change and are deliberately not included.

If this touches decisions/wax/

• Hash chain integrity: no change to chain mechanics. Business dates and typed money values live in the hashed payload, which puts them inside the tamper-evidence boundary. The canonical serialization of decimal amounts must be pinned in the hash specification before v2 activation, and WAX-0034 states that requirement.
• Event immutability: unchanged. No stored event is rewritten. No events exist yet, so the shapes change without upcasting. After release the same changes would need upcasters under WAX-0026.
• Schema ownership: unchanged. Modules still own their payload schemas. Wax adds two field kinds, money and temporal kind (instant or civil date), to the field registry that already carries PII and reference value kinds.
• Module boundaries: unchanged. Modules consume the money and date primitives from Wax and do not define their own.

Version bumps

• WAX-0012: major, 1.0 to 2.0, because the Decision text changes (instants versus civil dates).
• WAX-0001, WAX-0007, WAX-0019, WAX-0022, WAX-0023, WAX-0027, WAX-0028: minor, 1.0 to 1.1, with the Decision sections untouched.
• WAX-0034: new decision, Proposed 0.1.
• INDEX.md and README.md follow (the WAX-0012 sentence, a new WAX-0034 line, and a count of 53 decisions).

Checklist

• I read the decisions neighboring this change, not just the file I edited.
• New or retitled decisions have a matching line in INDEX.md, and front matter follows CONTRIBUTING.md.
• python3 scripts/validate.py --base main passes locally, or I am relying on CI to tell me.
• No pricing, rates, market or customer allocation, consumer data, or client-confidential information.
• Claims about law or regulation are flagged for verification, not asserted.
• Commits are signed off (DCO). If I forgot, I will post the retroactive sign-off comment per CONTRIBUTING.md.
• I license this contribution under CC BY 4.0 (prose) and Apache 2.0 (embedded code samples).

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