v2.3.0 — Ola S complete: the channel watches itself

v2.3.0 — Ola S complete: the channel watches itself

• S4: Channel hardening — webhook auto-verification with self-repair, silence detector with named alerts + auto-resolve on proof of life, order reconciliation, inbound cancellations with ledger witness + SHIPPED guard, integration draft protection, sync noise short-circuit (#63)
• S2-MATCH: Auto SKU matching — draft suggestions with human approve, conflict naming, mapping CSV export/import with dry-run (#58)
• CI integrity: E2E gate now fails the run and is a required check; Playwright artifacts uploaded on failure; main branch protection ruleset activated

Closes Ola S (S1 → S4): full channel contract + hardening, proven live against a real Shopify store.

Rollback: re-deploy v2.2.0 (all migrations in range are additive — safe). Release note: deploy-gating rule added to RELEASE_MODEL §3 after the Railway platform incident during this release (frontend must never outrun its backend).