* fix(reflect): prevent context_length_exceeded on large memory banks (#457)
The reflect agent's agentic loop accumulated tool-call messages across
iterations with no upper bound on token count, causing
context_length_exceeded errors on banks with 19K+ nodes.
Changes:
- Add proactive token-budget guard: before each call_with_tools, count
accumulated message tokens via tiktoken; if >= max_context_tokens and
evidence has been gathered, immediately synthesize from what was found
- Detect context-overflow errors specifically (_is_context_overflow_error)
and skip the retry path — retrying after overflow only makes it worse
- Truncate context_history in build_final_prompt to a 60K-token budget
so the fallback synthesis prompt itself cannot overflow
- Add HINDSIGHT_API_REFLECT_MAX_CONTEXT_TOKENS config (default 100000)
wired through config.py → main.py → memory_engine → run_reflect_agent
- Tests: unit tests for helpers + mock-LLM behavior tests + an
end-to-end integration test using a real LLM with max_context_tokens=1
* fix(reflect): derive final prompt context budget from max_context_tokens
Replace the hardcoded _FINAL_PROMPT_CONTEXT_BUDGET (60K tokens) with
a fraction of max_context_tokens (80%), so the fallback synthesis prompt
automatically scales with whatever context window is configured.