fix: separate lineage hash domains and preserve result semantics

[rynfar]

A changed tool result could retain the same lineage hash as the cached history: changing is_error from false to true resumed the old SDK session and still answered SUCCEEDED. Text could also impersonate tool blocks or inject message boundaries, and per-block proofs did not include the message role.

Use structured, domain-separated encodings for aggregate, message and block hashes. Preserve roles, boundaries, tool identities/arguments and result error status. Canonicalize JSON keys while retaining plain-string/text-block equivalence and ignoring opaque thinking/cache hints. The existing adapter/diagnostic renderer remains unchanged and no longer acts as a lineage proof.

Legacy hashes trigger complete replay through the validated #940 path, then subsequent turns on upgraded proxies resume normally. Alternating between old/new proxy versions can repeat this cost until all participating proxies are upgraded. SDK transcript files are never rewritten for migration.

Validation:

• Thirteen pure cases cover type/boundary/role confusion, errors, key ordering, media/cache hints, legitimate append, and legacy hashes. Initial 11-case baseline: 9 fail; two further controls added.
• All 10 new HTTP cases fail on main and pass after, including complete revised input delivery and one-time legacy migration followed by resume.
• Real client tool loop: main ignores the changed error flag and answers SUCCEEDED; the fix delivers the revised flag and answers FAILED. Legacy mapping replay preserves call arguments/result data and then resumes. Haiku and Sonnet × streaming/non-streaming all pass, with immutable source histories inspected using supported SDK APIs.
• Full npm test: 3,350 pass, one existing skip, zero failures. Typecheck/build pass.
• All four real E41 sequential/parallel × streaming/non-streaming controls pass. Both real undo-gap modes pass ordinary rollback, revised intermediate history and missing-checkpoint cases. Exact-head CI passes: Linux test/build, Windows smoke, container smoke and container build.

Fixes #887. Related to #872; this does not adopt its proposed arbitrary block-drop continuation.