Replace WAMR's contiguous 64KB malloc with an SD-backed page cache
(8 slots × 4KB = 32KB RAM window, CLOCK eviction). All WASM memory
access routes through page_cache_resolve() via #ifdef WAMR_USE_PAGE_CACHE
guards in the interpreter, memory instantiation, and enlargement paths.
Bulk memory ops (init/copy/fill) chunked page-by-page. Host function
access via linear_memory.zig routes through the same page cache.
Also includes WAMR component source, sleep helpers, deep sleep support,
ember-sdk additions, and launcher/UI improvements from prior work.
Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>