Pin @npcz/magic to 1.3.12

[0x2b3bfa0]

Reverts #1412; @npcz/magic is by far our most fragile dependency, and pkg is deprecated: the combination of both is just catastrophic.

RangeError: Invalid typed array length: 4294835611
    at new Int8Array (<anonymous>)
    at Object.write (/snapshot/cml/node_modules/@npcz/magic/dist/magic-js.js:8:44744)
    at Object.write (/snapshot/cml/node_modules/@npcz/magic/dist/magic-js.js:8:151332)
    at doWritev (/snapshot/cml/node_modules/@npcz/magic/dist/magic-js.js:8:144274)
    at _fd_write (/snapshot/cml/node_modules/@npcz/magic/dist/magic-js.js:8:144487)
    at wasm://wasm/00123836:wasm-function[176]:0x1b8f4
    at wasm://wasm/00123836:wasm-function[188]:0x1bdb2
    at wasm://wasm/00123836:wasm-function[189]:0x1be5f
    at wasm://wasm/00123836:wasm-function[416]:0x2afbb
    at wasm://wasm/00123836:wasm-function[160]:0x1acfb