feat(contract): Blinking Cursor site-forge — theme.js methods + THEME.md docs

[johndietz]

Blinking Cursor weekend — theme-starter (contract source of truth)

The theme contract, extended for site-forge. Byte-synced into konstruct-api's scaffold copy — a drift-gate test (TestContractSurfacesStayInSync) enforces all three surfaces agree.

Epics: civo/konstruct&202, &203, &206 (all closed; running on internal).

What's here (3 commits, +68 lines, 2 files)

• theme.js: 7 new methods matching the broker ops — forgeSite, forgeSiteJob, forgeSiteJobs, inferSite, forgeSiteUpdate, domainStatus, deleteSiteRepo.
• THEME.md: site-forge section — job phases, non-force update semantics, the 'never link a custom domain before serving:true' rule, two-step deletion contract, platform_url deep-link base, the /site-- eject-safe naming convention.

Review notes

• Pure additive docs + client methods; existing method signatures unchanged.
• Suggested merge order: LAST — theme-operator → konstruct-api → konstruct-ui → theme-starter — since the konstruct-api scaffold copy must land with (or before) this to keep the drift gate green.