SQL: explain plan walkthrough for analysts

Dialect: {{SQL_DIALECT}}

Query:
```sql
{{QUERY}}
```

EXPLAIN (or EXPLAIN ANALYZE) output:
```
{{PLAN}}
```

Explain to a data analyst (not a DBA):
1) Execution story in 5–8 bullets (order of operations).
2) Likely bottleneck with evidence from the plan.
3) 3 optimization ideas: index candidates (with columns), rewrite ideas, stats/maintenance notes — mark "verify with DBA" where needed.
4) What *not* to do (common mistakes).

If the plan is missing, say what to capture next.