Combined 1.8.0 batch 2: reversal fix, report iteration, replay companion, metrics-only mode - #632

Combined second batch for 1.8.0. Each member was reviewed and proven on its own branch; this branch merges them onto main and is verified as one tree.

Members (merged in this order)

• Keep a reversal's newly credited opening when its entry id had opposite-side history (fixes wrong positions, uncapped pyramiding and missing closed-trade rows after a reversal on a reused entry id; affected releases v1.1.0 through v1.7.0).
• Window buffers for technical-analysis series kept on main.
• Report channel contract and hosting jail budget contract (docs; docs/design: report channel contract #613, docs/design: hosting-jail budget contract #614).
• Annualization diagnostic uses the engine's initial capital on every report path.
• Opt-in report replay companion (report: opt-in replay extension (raw realized P&L, settlement markers, equity members, companion stream) #607).
• Metrics-only run mode (run_json: --metrics-only, a certified module takes the no-curve metrics route #630).
• Comment-only rewording of shipped source comments.
• Source clones skip the in-repo .ccache directory, so a whole-tree copy no longer races a running compile.
• In-process iteration of the default-path report columns: report["trades"] and report["equity_curve"] iterate lazily from the report spool again, report their length and support integer indexing; iteration must happen before the report's resources close.
• CHANGELOG entries for the above, and re-pointed source-line citations in two documentation pages (line numbers only).

Not in this batch

The live runner's report checkpoints (#598) and report accumulator (#617) move to the next minor release: testing showed a timing case that can leave a delivered order unacknowledged and a crash for modules whose handle is not an engine. Their pull requests stay open as drafts.

Verification

• Native live suite (all native shards, thread and address sanitizer legs) on this tree's code.
• Full verify and the corpus parity sweep on this exact head.
• Every member was reviewed independently before it was merged here.

🤖 Generated with Claude Code