Add a credit type: verified stewardship hour (VSH) — labor-time as a registry unit

Original Proposal Text

Adds ONE row to the x/ecocredit credit-type table via the standard governance method (Msg/AddCreditType, module Revision 2): abbreviation VSH, name "verified stewardship hour", unit "hours of verified ecological stewardship labor (verification method defined at the credit class or project level)", precision 6. THE PRECEDENT: this registry already prices labor-time — KSH, kilo-sheep-hour, is a live credit type whose unit is sheep-hours of grazing. VSH generalizes that to human stewardship labor: maintenance, restoration, and monitoring work verified as done. THE HONESTY BOUNDARY, stated up front: a VSH credit attests to VERIFIED LABOR under a verification method the credit class or project declares — it does not claim an ecological outcome quantity. Outcome-denominated types (C, BT) measure results; VSH measures the tended effort every result depends on, and no VSH batch should ever be marketed as tonnes avoided or sequestered. WHY THE CHAIN BENEFITS: classes, projects, batches, sales, and retirements under VSH are new activity in the module this chain exists for, and they let a buyer fund the verified maintenance of a real place directly — the demand side of ecological labor. WHAT IT DOES NOT DO: it mints no credits, spends nothing from any pool, obligates nobody, and privileges nobody — creating a class under VSH costs the same standing 5,000 REGEN credit_class_fee as any type, under the same allowlist setting (currently disabled: anyone may create a class). CONFIRM WITHOUT TRUSTING ME: the live credit-type table including KSH is at /regen/ecocredit/v1/credit-types; the class fee and allowlist setting are at /regen/ecocredit/v1/params. More details: https://vealth.net/regen/forum.html