v1.10.0: efficiency, bounded prompts + weighed record

Efficiency is a verifiable quality, because waste is measurable. Forum is already cheap-first (route before a model, judge only when flagged, resume reuses work, budgets cap runs, the content store dedups). This release closes the one waste path the engine introduced and makes efficiency visible.

• Bounded upstream injection: a data edge no longer injects an unbounded upstream output into the downstream prompt. Each injected upstream is capped (dispatch_plan(max_upstream_chars=...), default 8192) with a witnessed truncation marker; the full output stays in the upstream's result entry, so the record loses nothing and only the prompt shrinks. Bounds the growth that compounds down a deep plan.
• A weighed record: summarize reports payload_bytes (the UTF-8 byte weight of distinct witnessed payloads, an efficiency signal not a token count). forum bench shows whether a change made a run leaner; the CLI summary surfaces checkpoints, resumes, and payload weight.

Pure standard library, deterministic, no model in the loop. 230 tests, plus 2 gated real-model tests.

Install: pip install forum-engine