fix(message): preserve event timestamps and validate rules

[rayrayraykk]

Linked Issues

• Related to feat: align TypeScript SDK with AgentScope Python incrementally #49
• Follow-up to feat(message): align message contracts with Python #52

Description

The review of #52 identified three regressions in message event handling and wire validation. This PR fixes only those findings:

• Preserve each event's created_at when reconstructing content blocks, including nested tool-result blocks. This restores deterministic replay of delayed streams.
• Validate ToolCallBlock.suggested_rules as permission rules instead of accepting arbitrary values from serialized payloads.
• Clone usage before the Desktop React state updater applies a MODEL_CALL_END event, so repeated updater calls do not mutate or double-count the previous state.

The existing streaming test now keeps its clock fixed while replaying events, and a focused parser test covers valid and invalid permission rules. No new public API, dependency, generated artifact, or development document is added to the repository.

Verification:

pnpm --filter @agentscope-ai/agentscope build
pnpm --filter @agentscope-ai/agentscope exec jest --runInBand --silent
pnpm build:desktop

Core: 19 suites, 129 tests passed. The Core ESM/CJS/declaration build and Desktop typecheck/build passed. Changed files passed ESLint, Prettier, and git diff --check. A local double-invocation check confirmed the Desktop updater leaves the previous usage object unchanged.

Checklist

• This PR is linked to a related issue (see above)
• Code has been formatted with the repository's Prettier and ESLint hooks
• Related documentation has been updated (not applicable: bug fix with no public API change)
• All tests are passing (pnpm test equivalent shown above)
• Code is ready for review