fix: restore strict all-feature Clippy validation

[redxzeta]

Strict cargo clippy --all-targets --all-features -- -D warnings fails on clean upstream cf82f5d with current stable Rust: constant-size chunks_exact, redundant references to cached Postgres handles, and temporary vectors used only as slices.

Use array chunks for float decoding, pass cached handles directly, and use arrays in the two remote-document test fixtures. These focused edits preserve behavior and remove the causes without suppressing lints, changing checks, or altering feature defaults. Separate prerequisite for diagnostics PR #81.

Validation: cargo fmt --all -- --check, git diff --check, and strict all-target/all-feature Clippy pass. Remote features are compile-checked; no provider services are started or configured. Full runtime validation is recorded on PR #81 after integrating the independent embedding-bounds fix (#82).

Hosted CI run 37177863735 for head 9e68b72 reports action_required. The run page explicitly says it awaits maintainer approval; the API reports zero jobs, with no hosted validation result. The authenticated contributor account has read-only upstream permissions and cannot approve the run. Required PR review and successful hosted CI remain pending.

[redxzeta]

Investigated CI run 37177863735 on head 9e68b72365dde8e5f186362eb1ac433a6cfcee2a. GitHub explicitly reports that the workflow awaits maintainer approval. No jobs started and no logs are available, so this is an approval gate with no hosted test/build result.

An upstream maintainer must approve the run; the authenticated contributor account has read-only upstream permissions. No source or workflow change, check suppression, or rerun was performed. The focused local validation remains as recorded above; required review and successful final-head hosted CI remain pending. T3 watching remains enabled.