release: 0.3.0

[hanslemm]

Cuts 0.3.0 — the release that makes advise available. 182 commits and five development
batches have landed on main since v0.2.0, all of it invisible to anyone who pip installs
the package.

• __version__ → 0.3.0
• ## [Unreleased] → ## [0.3.0] - 2026-08-03

The changelog section is rewritten, not just retitled. It had accumulated across five
batches and read as a diff against unreleased intermediate states — "ADV001 now requires…",
"ADV003 no longer proposes…" — which says nothing to someone meeting advise for the first
time here. More importantly the whole ### Fixed section described bugs in code that has never
shipped, which implies users hit them. Four of its ten entries weren't fixes at all but features
(--dry-run, connection resolution, the optional extras, cursor/COPY unwrapping), and two were
internal test infrastructure that belongs in git history.

Fixed is therefore gone, with a one-line note explaining that a first release has no
previously-released behaviour to fix. Its features moved to Added, and the two shipped
behaviours worth keeping — the --ddl line-boundary guarantee and ADV004's coverage disclosure —
are now stated as properties of what ships rather than as repairs.

A Known limitations section carries what a user most needs at install time: Redshift's
introspection SQL has never been executed against a live cluster, precisely what is verified
(connection path against a real server, every statement syntax-checked and proven bindable), and
the invitation to check it with --dry-run before pointing it at production.

Two accuracy fixes found while editing: the reconciliation bullet said "the eight rules" when
there are now sixteen across three families, and described only Postgres's prefix collapse —
Redshift's strategy collapse (DISTSTYLE ALL withholding DISTKEY, so an operator doesn't run
one hours-long rewrite and then a second undoing it) was undocumented. And
co_occurring_fingerprints, a public --json field, survived only inside a bullet whose delta
framing I dropped, so it is now stated on its own terms.

Version choice: minor, not major. advise is a new command; the existing complexity, lint,
perf and check surfaces are unchanged.

After merge I'll push the bare-semver tag 0.3.0 — not v0.3.0 — which triggers release.yml
to build, publish to PyPI via trusted publishing, and create the GitHub release.

Verification

• 980 passed, 23 deselected — zero skips
• 23 passed integration against live postgres:16
• ruff check, ruff format --check, mypy src/sqlquality clean
• sqlquality --version reports 0.3.0