post(TRI-1431): advance main with r26.06 upstream-tracking cherry-picks

[mc-nv]

What does the PR do?

Advances main post-26.05 toward the 26.07dev_user container train (tracks upstream 26.06).

Cherry-picks 3 commits from r26.06:

• 18c97e4a1 — feat(TRI-1118): add --release-version + PEP 440/817 wheel scheme
• 08e185ea3 — build(TRI-1421): add libssl-dev to base image
• 3578598bd (was 690f9dd2c) — docs(TRI-1427): add 26.06 compatibility entries

Skipped from r26.06:

• d898a0fe6 (TRI-1406 prepare for 26.06 — release-only version bump, regresses main).
• a4aab2b7e (docs(server) update README and versions for r26.06 — release-only).
• e5f5faf75, fe1f873f5, 430ad7101 — already on main via squash; empty after merge.
• d4d7275d5 (fix(qa) TRT 11 strongly-typed cast for plan_float* output dtype) — needs manual conflict resolution on qa/common/gen_qa_models.py between main's uint8-specific cast path and r26.06's generic trt_cast_tensor helper. Follow-up PR.

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:

• post (advance-default-branch — release lifecycle)

Related PRs:

• feat(TRI-1118): add --release-version + PEP 440/817 wheel scheme (cherry-pick) core#505
• build(version): Bump version for protobufjs (cherry-pick) client#905
• ci(TRI-1406): prepare ONNX Runtime backend for 26.06 (TRT 11, OV 2026.2, CCCL fix) (cherry-pick) onnxruntime_backend#345
• feat: Add TensorRT Multi-Device (multi-GPU) inference support (cherry-pick) tensorrt_backend#122
• chore(versions): align tutorials examples with 26.06 release train (cherry-pick) tutorials#152
• post(TRI-1431): advance model_analyzer post-26.06 (docs + container tags) model_analyzer#1027

Where should the reviewer start?

• The 3 cherry-pick commits — each is self-contained and links back to its source PR ((cherry picked from commit ...)).
• Confirm TRITON_VERSION stays at 2.71.0dev and build.py defaults still target upstream 26.06 / container 26.07dev.

Test plan:

• Run the integration CI via the tritonserver pipeline with TRITON_CONTAINER_VERSION=26.07dev_user.
• L0_infer / L0_batcher / L0_sequence_batcher across the configured backends.
• CI Pipeline ID: TBD

Caveats:

• d4d7275d5 (TRT 11 strongly-typed cast) deferred — manual conflict resolution required.

Background

Standard post-NGC-release "advance main" sweep. The new train uses upstream 26.06 (just released) and the dev branch becomes 26.07dev_user.

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

• Resolves: TRI-1431