fix(session-analyzer): satisfy Rust 1.93 clippy gate

[AlexMikhalev]

Summary

Restore the repository-wide Rust 1.93 CI gates by applying semantics-preserving let-chain refactors to terraphim-session-analyzer.

• remove 28 clippy::collapsible_if findings across library, binary, connector, and test targets;
• replace one map_or(true, …) with Clippy’s equivalent is_none_or suggestion;
• add no lint suppressions;
• include the one-line pre-existing terraphim_update rustfmt correction required by the workspace formatter gate.

RED → GREEN evidence

Initial workspace clippy stopped after 19 library-target errors. Once those were fixed, --all-targets exposed ten additional pre-existing binary/test-target findings (9 collapsible-if and 1 unnecessary-map-or). All are corrected without behavior changes.

Final verified gates:

• cargo fmt --all -- --check: pass.
• cargo clippy --workspace --all-targets -- -D warnings: pass.
• cargo test -p terraphim-session-analyzer: pass:
  • 116 lib tests;
  • 115 bin tests;
  • 20 filename-filter tests;
  • 42 integration tests;
  • 23 knowledge-graph tests;
  • 3 doctests;
  • 0 failed.
• git diff --check: clean.

Tracking

Fixes terraphim-ai#3211 and unblocks workspace CI for terraphim-clients#9.

Scope

No lint allow, dependency, version, release, grep behavior, or generated artifact changes.