[bferanmi806-sketch]

Summary

• Add a configurable model middleware that summarizes oversized text tool results before the next agent model call.
• Bound summarizer input and output sizes, preserve tool call identity, and fall back to original output if summarization fails.
• Document the prebuilt in the middleware catalog.

Related to #1636
Closes #1740

Verification

• Focused tests: 7 passed.
• Ruff check and format passed.
• mypy passed for the new implementation.
• uv run mkdocs build --strict passed.
• Full unit-test collection is blocked by unrelated optional dependencies absent from this environment (FastAPI, DuckDB, NumPy, etc.).