Step 17b: bytecode-compiled text-layout, WASM library import fix

- text-layout.sx added to WASM bytecode pipeline (9K compiled)
- Fix multi-list map calls (map-indexed + nth instead of map fn list1 list2)
- pretext-layout-lines and pretext-position-line moved to library exports
- Browser load-sxbc: handle VmSuspended for import, copy library exports
  to global_env after module load (define-library export fix)
- compile-modules.js: text-layout in SOURCE_MAP, FILES, and entry deps
- Island uses library functions (break-lines, pretext-layout-lines)
  instead of inlining — runs on bytecode VM when exports resolve

Known issue: define-library exports don't propagate to browser global env
yet. The load-sxbc import suspension handler resumes correctly but
bind_import_set doesn't fire. Needs deeper investigation into how the
WASM kernel's define-library registers exports vs how other libraries
(adapter-html, tw) make their exports available.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

shared/static/wasm/sx_browser.bc.wasm.js

@@ -1792,7 +1792,7 @@
             blake2_js_for_wasm_create: blake2_js_for_wasm_create};
    }
    (globalThis))
-({"link":[["runtime-0db9b496",0],["prelude-d7e4b000",0],["stdlib-23ce0836",[]],["re-9a0de245",[2]],["sx-982ed992",[2,3]],["jsoo_runtime-f96b44a8",[2]],["js_of_ocaml-651f6707",[2,5]],["dune__exe__Sx_browser-acaac3c1",[2,4,6]],["std_exit-10fb8830",[2]],["start-f808dbe1",0]],"generated":(b=>{var
+({"link":[["runtime-0db9b496",0],["prelude-d7e4b000",0],["stdlib-23ce0836",[]],["re-9a0de245",[2]],["sx-80a20737",[2,3]],["jsoo_runtime-f96b44a8",[2]],["js_of_ocaml-651f6707",[2,5]],["dune__exe__Sx_browser-08c26bf2",[2,4,6]],["std_exit-10fb8830",[2]],["start-f808dbe1",0]],"generated":(b=>{var
 c=b,a=b?.module?.export||b;return{"env":{"caml_ba_kind_of_typed_array":()=>{throw new
 Error("caml_ba_kind_of_typed_array not implemented")},"caml_exn_with_js_backtrace":()=>{throw new
 Error("caml_exn_with_js_backtrace not implemented")},"caml_int64_create_lo_mi_hi":()=>{throw new