v1.3.0 — persisted ports and in-proxy navigation

First tagged release (the package has shipped as 1.3.0 since the persist-ports-and-navigation work).

• Keep the port config across sessions; navigation stays inside the proxy
• Editable URL bar (port, path, proxy path or dev-server URL)
• Fragment-link safe (#section jumps inside the page), root-relative resources rewritten
• Documented, tested: 32/32 tests on node --test incl. the Playwright e2e suite (POST/body forwarding, cookies, prefix idempotency)