fix: read SGLang dictionary startup identity

[iraj465]

SGLang can emit startup settings as server_args={...}. Hyperloom currently recognizes only server_args=ServerArgs(...), leaving the observed model/configuration identity empty and the same-configuration reference unverified when launch arguments are unavailable. Read both forms through the existing identity field allowlist and literal-value bounds.

The parser handles wrapped records, nested values and quoted delimiters, caps log reads, and treats malformed or excessively deep expressions as unavailable evidence. Identity records continue to describe observed settings without supplying launch argv. This repairs evidence collection; it does not change benchmark acceptance thresholds or claim a performance improvement.

• Linked issue(s): companion GEAK parser fix in fix(interface): read SGLang dictionary startup identity GEAK#471 (independent changes to the two consumers).
• Tests: 79 focused tests passed, including 50 parser cases and 29 existing GEAK handoff cases. The full local suite (pytest -q -n 2 -m "not critic_agent_e2e and not robustness_agent_e2e and not targeted_build_e2e") completed with 22,754 passed, 55 skipped and four failures. All four reproduce on unchanged base 2cc382a8: three robustness idle-observation tests and test_a_restart_past_the_limit_becomes_terminal (missing final.json). No new test failures were identified.
• Hosted CI: all 30 checks passed, including the Python 3.10/3.11 test shards, coverage, lint, license and secret checks; the main-only deployment and test-duration update were skipped.
• Static checks: Ruff lint/format, REUSE and git diff --check pass. Mypy reports the identical baseline diagnostic set (920 errors across 156 files), with none added.
• CHANGELOG.md entry under [Unreleased]: yes.
• Breaking changes: no.
• PR addresses single concern: yes, SGLang startup identity parsing.
• Root cause is upstream: no; Hyperloom owns this log parser. GEAK's separate parser has the same compatibility gap and is addressed by the linked companion PR.