Fix channel list pagination query

[sionsmith]

Summary

• Fix channel list so it does not send $top to the Microsoft Graph list-channels endpoint.
• Add a no-$top paginated GET helper that still supports @odata.nextLink for --all-pages.
• Add mocked regression tests that reproduce the Graph-style $top rejection and verify the fixed channel-list path.
• Update transitive quinn-proto lockfile pin from 0.11.14 to 0.11.15 to resolve RUSTSEC-2026-0185 found during release checks.

Closes #23

Verification

• cargo fmt -- --check
• cargo test --all-targets
• cargo check --all-targets
• cargo clippy --all-targets -- -D warnings
• cargo audit exits cleanly with only the existing allowed rand warning