[psteinroe]

Hover now uses the name resolver from #867. Before, it looked names up in the snapshot, so an overloaded function listed every overload and columns were guessed by name.

Before / after

create function pick(i integer) returns integer language sql immutable as 'select i';
create function pick(t text) returns text language sql immutable as 'select t';

select pick(1);
--     ^ hover

Before, hover showed both functions:

### `public.pick(i integer) → integer`
---
### `public.pick(t text) → text`

Now it shows only the overload that pick(1) resolves to:

### `public.pick(i integer) → integer`

How

• walk_statements is a new workspace helper, extracted from pull_inlay_hints and shared with it. It walks the file like the analyser, with the Catalog and Session following the statements. Hover uses it to resolve the innermost statement at the cursor with collect_references, and passes the references whose span contains the cursor to pgls_hover (new field OnHoverParams::references).
• pgls_hover maps a reference of the hovered kind to the snapshot object:
  • Functions: the snapshot function with the same schema, name and input argument types. Types created in the file are matched loosely, and it gives up if more than one candidate matches.
  • Columns of catalog relations: the column by schema, table and name, which covers aliases and unqualified columns in joins.
  • Relations: the table the search path resolves to.
  • CTE and subquery columns: they aren't in the snapshot, so they get a small hover with their inferred type (c.label, text - CTE column).
• When there's no unique reference (ambiguous call or column, unknown types, an unparsable statement), hover falls back to the name-based lookup exactly as before. Without a database there's still no hover.
• Hover now takes the innermost statement at the cursor, so it also works inside SQL function bodies. Before, the outer CREATE FUNCTION was used and the body was just a string literal to tree-sitter.

Risks

• Each hover now walks the file up to the cursor and applies its DDL, as inlay hints already do. This is fine for typical files but adds cost to hover on very long ones.
• Functions created in the file still show the reduced headline of the materialized snapshot (no argument list). That's unchanged, but now it's a single block.

[psteinroe]

Folded into #861 (now one PR for inlay hints, resolved references and hover). GitHub shows this as merged into feat/inlay-hints, not main.