Update changelog for 3.2.2

[kmcginnes]

Description

Adds the Release 3.2.2 section to Changelog.md, covering the eight PRs merged since v3.2.1. Documentation only, no code changes.

The release is a scale story: schema sync now batches its discovery requests, one cause of the Schema View stall is removed, and a proxy IAM credential failure that surfaced under the same load is fixed.

Structured like the 3.2.1 section: a short summary, themed sections, then ### All Changes with the full PR list and the compare link.

Two things worth a reviewer's attention:

1. The Schema View claim is deliberately scoped. Resolve vertex icons through an icon registry to fix schema-view lockup #2102 fixed the TanStack Query fan-out stall. The separate Cytoscape stylesheet stall is not in this release, so the notes say icon loading no longer stalls the view and that more improvements are coming, rather than claiming the view is fixed on large schemas.
2. The concurrency change is described by outcome only. Replace fixed-batch barrier with an eager concurrency pool #2096 also lowered the in-flight limit from 10 to 4, so the notes say a slow request no longer holds up the sync rather than implying an unconditional speedup.

Validation

• Documentation only; no code, dependency, or lockfile changes.
• pnpm check:format passes.
• PR titles, authors, and numbers in ### All Changes verified against the merged PRs on main.
• Every user-facing claim checked against the merged implementation rather than the PR descriptions alone.

Related Issues

None.

Check List

• I confirm that my contribution is made under the terms of the Apache 2.0 license.
• I have verified pnpm checks passes with no errors.
• I have verified pnpm test passes with no failures.
• I have covered new added functionality with unit tests if necessary.
• I have updated documentation if necessary.