Dynamic aps schema keys projection + smoke for user keys

[0xLeif]

Part of 1.0 prep (private). From RFC docs/design/dynamic-schema.md.

• aps schema keys project live schema.json; add userSchema.formatVersion + userSchema.hash
• Bump static schemaVersion only when contract document shape changes
• Smoke: materialize + key add/remove round-trip in smoke.sh / smoke.ps1

Depends on: registry + key CLI issue

[0xLeif]

Implemented in PR #65 (branch cursor/issue-62-dynamic-schema-runtime). Releasing claim label.