fix(runtime): re-authenticate a copied paging Read with its dispatch

[ggbdpq]

Summary

Fixes #5329

Editing an earlier message fails with canonical_args_hash_conflict whenever the model paged a truncated tool result: the ledger clone rewrites a copied Read/ArchiveRead call's args to name the copied tool result, but the paired tool_dispatch event was copied verbatim and kept the hash of the source's args. The copy then fails its own T1 re-scan (importConversationCopyRuntimeEvents → scanToolLedger), and every revision retry is refused as a corrupt ledger — while the source Session's ledger is, in fact, fine.

The fix lives where the rewrite happens: during the identity-rewrite pass, the clone records the rewritten args per (invocation, tool call) and re-authenticates the paired dispatch's canonicalArgsHash, so the copied ledger authenticates the args it actually carries. Dispatches without a recorded hash keep their shape. The existing copy tests never caught this because their Read calls had no paired tool_dispatch event, leaving the scanner nothing to compare.

Verification

Check	Result
New regression test (clones a ledger whose paging Read is paired with a dispatch that authenticated the source args)	fails with the issue's exact canonical_args_hash_conflict before the fix; passes after, with the dispatch hash equal to the rewritten args
Full conversation-copy suite	15/15 pass on this branch; the 13 failures seen locally fail identically on clean upstream/main in this environment (Windows sqlite-cleanup EBUSY in test cleanup, one per failing test) — CI is expected to run them clean
biome check on both touched files	clean

AI use

Implemented with GLM-5.3-Flash (ZCode); the reproduction, fix, and tests were verified locally as described above.

Checklist

• The patch targets the shared clone path, not one caller's symptom
• A regression test pins the issue's exact failure mode (paired dispatch present)
• No new dependencies; one helper import from the existing @maka/core/tool-args-identity
• Local environment caveats disclosed above (13 EBUSY cleanup failures pre-exist on clean upstream locally)