1. Parser+codegen: bare reassignment `x = expr` inside an if-body
was compiling to three orphan expressions with no store. Now
emits a real assignment.
2. Runtime json_get: dot-path segments that are all digits now
correctly traverse array indices. `json_get(s, "0.field")` works.
3. Runtime HTTP writer: response bodies starting with
`{"__status__":<int>,...}` now set the HTTP status header to
that value and strip the marker from the served body. Existing
404/401/503 paths in product code now produce real status codes
instead of HTTP 200 with the status hidden in the body.
Self-host fixed point holds: gen2 == gen3 byte-identical.
Snapshot tagged at dist/platform/elc.20260502-1231-self-host.
Backlog: bl-c121edda
Will Anderson
742bd0b4f9