postgres_dba 7.0 — 34 diagnostic reports for psql

[postgres_dba](https://github.com/NikolayS/postgres_dba) 7.0 is a major update to the interactive psql-based diagnostic toolkit for Postgres. No extensions required — just `\i start.psql` and explore 34 reports covering:

- **Bloat & vacuum analysis** (v1, v2) — activity, progress, autovacuum queue
- **Table & index health** (i1–i3) — unused indexes, redundant indexes, non-indexed FKs
- **Query analysis** (s1–s3) — pg_stat_statements top queries and workload profile
- **Tuning** (t1, t2) — storage parameters, config recommendations
- **Table/index size estimation** (b1–b6) — alignment padding, bloat, buffer cache
- **Lock trees** (l1) — who's blocking whom
- **Corruption checks** (c1–c4) — 4-level amcheck suite from quick scans to full heap verification
- **Memory analysis** (m1) — buffer cache contents by relation

**What's new in 7.0:**

- 7 new reports: b6 (buffer cache analysis), s3 (workload profile), c1–c4 (amcheck corruption detection), m1 (buffer cache)
- WAL and replication info added to the system overview (report 0)
- CI on Postgres 13–18
- PG17 compatibility fixes for pg_stat_statements column renames
- Modernized README with badges, per-report descriptions, and optional extension table

Works on Postgres 13–18. Just clone the repo and run.

Links:

- Repository: [github.com/NikolayS/postgres_dba](https://github.com/NikolayS/postgres_dba)
- Release notes: [RELEASE_NOTES.md](https://github.com/NikolayS/postgres_dba/blob/master/RELEASE_NOTES.md)