feat(ui): support connect handlers on page dots

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Summary

• add jaws.ConnectHandler as a page-dot adapter to the existing Request ConnectFn lifecycle
• install only the direct ui.Handler dot callback before page template execution, preserving nested-template and arbitrary-dot behavior
• document the lifecycle in godoc, package guides, and the JAWS skill, with a compile-checked synchronized example
• cover the eight requested lifecycle, ordering, error, nesting, and concurrency cases with real HTTP/WebSocket tests

Compatibility

A top-level ui.Handler dot that already defines the exact method JawsConnect(*jaws.Request) error will now receive connection callbacks. Nested template dots are not discovered.

Validation

• go generate ./...
• go vet ./...
• gofmt -l .
• staticcheck ./... (CI-pinned revision)
• golangci-lint run (v2.13.1)
• gosec ./...
• go build ./...
• JAWS_REQUIRE_NODE=1 go test -race ./...
• JAWS_REQUIRE_NODE=1 go test ./...

Closes #377