perf(ai): run_sql seeks trace-id lookups through trace_index and stops at the row cap - #1960

🟢 Confidence 10/10 · safe to merge
The sql-identifiers edits come from the base branch, and F5 cannot fire: only a statement-terminal LIMIT matches the end-anchored OWN_LIMIT.
_{no findings · tests covered · risk medium}

run_sql now seeks literal trace-id reads through trace_index and truncates at the 1,000-row cap with an atRowCap notice instead of failing. The seek is added only where it cannot change rows, and the cap notice stays truthful. Safe to merge.

• withTraceIndexSeek ANDs the trace_index seek onto an unbounded literal trace-id conjunct
• run_sql falls back to the SQL as written when the seeked form is refused as invalid SQL
• truncateAtCap makes the row-cap wrapper fetch 1,000 rows instead of 1,001
• atRowCap is reported unless the statement's own terminal LIMIT asked for a full page

Fixed since the last review

• ✅ F5 · limitedWithinCap reads a subquery LIMIT as the statement's own cap

_{c25d423 · Updated on every push. Reply "won't fix" to dismiss a finding, or mention @maple-review-bot to ask about one.}