feat: add SmolAgents integration with Hindsight memory tools

[benfrank241]

Summary

• Adds hindsight-smolagents package under hindsight-integrations/smolagents/
• Three native SmolAgents Tool subclasses: HindsightRetainTool, HindsightRecallTool, HindsightReflectTool
• create_hindsight_tools() factory and memory_instructions() helper for system prompt injection
• 81 unit tests, lint clean
• Docs page, sidebar entry, integrations grid entry, and HuggingFace icon

Design notes

• bank_id is baked in at construction time (SmolAgents has no RunContext equivalent)
• Sync forward() methods call the Hindsight Python client directly
• Follows the same config/error/tools module pattern as hindsight-agno

Test plan

• cd hindsight-integrations/smolagents && uv run pytest tests/ -v — all 81 tests pass
• uv run ruff check . && uv run ruff format --check . — lint clean
• Manual end-to-end: start API, retain/recall/reflect against a live bank
• Docs page renders and icon displays in integrations grid
• ./scripts/release-integration.sh smolagents recognizes the integration name

[nicoloboschi]

Force-pushed a rebase + review fixes (was 074f17a, now fff3134).

Rebased onto current main and resolved three conflicts (scripts/release-integration.sh, hindsight-docs/src/data/integrations.json, .github/workflows/test.yml) — the older merge commit 074f17ac is gone. Branch is now 4 commits ahead of main: the original three plus one follow-up.

Fixes applied (commit fff31345):

• Added smolagents to the consolidated INTEGRATIONS table in hindsight-dev/hindsight_dev/generate_changelog.py. Without this the release script aborts at the changelog-generation step (this was originally three parallel lists; refactor(release): single integration table in generate_changelog #1314 collapsed them into one, but the new integration still needs an entry).
• Added a sidebar link in hindsight-docs/sidebars.ts. The docs page existed but wasn't reachable from navigation.
• examples/interactive_test.py: ruff F541 (f"" with no placeholders) and I001 (import order).
• ruff format unwrapped a few paren-wrapped expressions in tools.py.

Verified locally: uv run pytest tests -q → 81 passed, ruff check/ruff format --check → clean.

Things I left for you to decide (not blocking, but worth a thought):

• HindsightRetainTool._ensure_bank (tools.py:85-93) catches every exception during create_bank and still adds the bank to _created_banks — auth/network failures get silently filed away, then retain proceeds against a bank that may not exist. Maybe narrow the catch to "already exists" cases?
• memory_instructions returns "" on any exception (tools.py:371-373). Comment says "shouldn't block the agent" — fair, but it also swallows e.g. AttributeErrors during refactors. A logger.warning(..., exc_info=True) would help.
• Sync Hindsight client inside SmolAgents Tool.forward is reasonable since SmolAgents is sync top-level, but the sync wrapper uses loop.run_until_complete and will raise if the agent is ever invoked from inside a running event loop (FastAPI handler, etc.). Worth a note in the docs or README.