fix(ai): admit bounded assistant lifecycle reuse

[first-assist]

Summary

• admit a later completed-identifier reuse only when both lifecycle item types are exactly agentMessage
• retain fail-closed handling for active duplicates, type changes, reasoning, tool and web-search reuse, malformed correlation, and over-limit turns
• count tracked lifecycle starts independently so identifier reuse cannot bypass the 256-start ceiling
• release graphql-orm-ai 0.96.1 with aligned lockfiles and migration/release documentation

Verification

• full multi-provider test matrix
• isolated Codex app-server test, Clippy, and Rustdoc lanes
• warnings-denied combined Clippy and Rustdoc
• PascalCase naming test and Rustdoc
• PostgreSQL and MSSQL compile-only lanes
• SemVer, package release policy, deterministic release manifest, documentation, dependency-boundary, inventory, formatting, and committed-diff checks

Security

The compatibility allowance is limited to a completed, same-type, side-effect-free assistant message. It does not admit duplicate-active identifiers or any tool lifecycle reuse.

Documentation impact

• Documentation updated
• No documentation impact