[kvinwang]

Problem

#1024 turned off HTML escaping in toDeterministicJSON, but encoding/json escapes U+2028 and U+2029 regardless of SetEscapeHTML(false). Python (ensure_ascii=False), JS (JSON.stringify) and Rust write them raw, so any compose containing either character gets a Go-only digest. For {"runner":"docker-compose","docker_compose_file":"a
b
c \\u2028"}:

SDK	sha256
Python / JS	bf62f89b764e0b5393d31efd5480bcfaeb9ffdc3609aa6de021ba551e9311ade
Go before	cc33d87b0ef663d8256fa948b10a7b66e98fbe63d10207110a558a215070e0ff
Go after	bf62f89b764e0b5393d31efd5480bcfaeb9ffdc3609aa6de021ba551e9311ade

Fix

After encoding, rewrite 
/
 escapes to the raw characters. A plain string replace would be wrong: the six characters 
 in the content encode as \\u2028, which contains 
. The rewrite walks escape pairs, so an escaped backslash is copied through untouched.

Verification

• New TestLineSeparatorsAreNotEscaped pins the canonical bytes (both separators plus a literal 
); it fails on next and passes here.
• Hashes in the table computed with Python 3 json.dumps(sort_keys=True, separators=(",", ":"), ensure_ascii=False), Node JSON.stringify, and GetComposeHash.
• go test ./...: the same 26 tests fail before and after, all needing /var/run/dstack.sock (no simulator running); everything else passes.