chore: Update default branch to track 1.57.0 / 26.08

[mc-nv]

^{CI (internal): [#57177072](http://tritonserver.local/ci/pipelines/57177072)}

What does the PR do?

Advances main to track the next development release now that the current train is at code freeze. Bumps Model Analyzer version and its Triton container base:

• VERSION: 1.56.0dev → 1.57.0dev
• Dockerfile MODEL_ANALYZER_VERSION → 1.57.0dev, MODEL_ANALYZER_CONTAINER_VERSION → 26.08dev

Checklist

• PR title reflects the change and is of format <commit_type>: <Title>
• Changes are described in the pull request.
• Related issues are referenced.
• Populated github labels field
• Added test plan and verified test passes.
• Verified that the PR passes existing CI.
• Verified copyright is correct on all changed files.
• Added succinct git squash message before merging.
• All template sections are filled out.

Commit Type:

Uses chore (mechanical version-tracking bump; not in the list below).

• build

Related PRs:

triton-inference-server/server#8872

Where should the reviewer start?

VERSION and the ARG MODEL_ANALYZER_VERSION / ARG MODEL_ANALYZER_CONTAINER_VERSION lines in Dockerfile.

Test plan:

Version-string-only change; validated by the standard CI build.

• CI Pipeline ID: 57177072

Caveats:

None — mechanical version bump.

Background

Routine code-freeze step: once a release branch is cut, main advances to the next dev version so post-freeze work targets the upcoming train.

Related Issues: (use one of the action keywords Closes / Fixes / Resolves / Relates to)

• Resolves: TRI-1544