fix: nested inline object literals use correct struct type (#36)

[cs01]

Summary

• Fixes nested inline object literals generating wrong struct types in native compiler
• { start: { x: 10, y: 20 }, end: { x: 30, y: 40 } } now correctly allocates inner objects as %Point instead of inheriting outer %Line type
• Root cause: native compiler reads garbled .type field on inner AST expressions ("o" + garbage instead of "object"), so the valueExpr.type === "object" check always failed
• Fix: detect object literals using charCodeAt(0) === 111 (ASCII 'o') instead of full string comparison, then call generateInterfaceObject directly with the resolved inner interface type
• Unskips nested-inline-object.ts test (was @test-skip since issue add http response/request headers, serveEmbedded, and header tests #36)

Test plan

• JS compiler: TEST_PASSED
• Native compiler: TEST_PASSED (was FAIL start: 0,0)
• verify:quick passes (tests + Stage 1 self-hosting)