feat(go): PostgREST/Supabase query dialect in generated services (parity with TS #36/#56-#60)

[cultron]

Summary

Ports the @apso/crud PostgREST/Supabase dialect to the Go (Gin+GORM) generator, so generated services accept the same PostgREST URL conventions as our TypeScript services (@apso/crud + @apso/postgrest-request). This is the Go port of the TS dialect; the incumbent nestjsx dialect is unchanged (byte-identical output — ParseQueryParams is retained and still delegates to the nestjsx parser).

Extends (does not replace) the generated utils/query.go and threads a dialect step through the generated handler + service.

Dialect detection (mirrors crud/src/dialect.ts)

• X-Crud-Dialect header wins: postgrest | nestjsx, any other value ⇒ 400.
• Else param-shape: select/order or a bare col=op.value ⇒ postgrest; fields/filter/join/sort/s/or/per_page ⇒ nestjsx; both families ⇒ 400 (ambiguous); limit/offset/page/cache are dialect-neutral; default nestjsx.
• Note (parity with TS): or is a nestjsx-signal key, so a PostgREST or=() group must be forced via the header (or accompany another postgrest signal without a nestjsx one). select + or together is an intentional 400.

Operators / behaviors implemented (parity with postgrest-parser.ts)

• select: select=a,b, alias:col output rename ⇒ col AS alias (CLI first pivot: new command surface, architecture refactor, tests #57), ::type cast stripped, embeds rel(cols) ⇒ GORM preloads.
• filters col=op.value and not.<op>: eq, neq, gt, gte, lt, lte, like, ilike, in, is (incl. is.null/is.true/is.false, not.in, negations). like/ilike translate the PostgREST * wildcard to SQL % and apply the pattern verbatim.
• logical groups: or=(...) / and=(...), including nested or(...)/and(...), ANDed with the flat column filters (Plat 1269 #56).
• order: order=col.asc|desc[.nullsfirst|nullslast] ⇒ ORDER BY col DIR [NULLS FIRST|LAST].
• pagination / response shape: PostgREST limit/offset ⇒ bare JSON array (no envelope), offset windows the array (feat: MCP server + CLI modernization #58); nestjsx keeps its {data,count,total,page,pageCount} envelope.
• errors: unknown filter/sort/select column on the postgrest path ⇒ 400 (*QueryError), not 500 (Feature: auto-detect codegen/schema issues from real usage and (opt-in) auto-file GitHub issues #60); nestjsx still silently drops unknown columns. Bad header / ambiguous mix / bad operator ⇒ 400.

Deferred

• cs, cd, ov, fts (and other advanced operators) — recognized and rejected clearly as deferred (Plat 1288 #54), never silently mishandled.
• Embedded ON-clause filters (primaryKeyType: "uuid" generates a non-generated @PrimaryColumn() → every insert fails with null id #59) are scoped out on the Go path. The Go embed path uses GORM Preload, which has no embed-level predicate, so an rel.col= filter is treated as a root filter rather than shaping only embedded rows. select embeds still project relation columns. This is the only intentional gap vs the TS TypeORM join path.

nestjsx unchanged

The nestjsx parsing, filter/or/sort/join handling, and envelope response are untouched. ParseQueryParams still exists and delegates to parseNestjsxParams.

Tests

• Generator tests assert the emitted Go covers: dialect detection + header precedence, the full operator map, deferred-op rejection, or=/and= groups, alias rename, order nulls, bare-array + offset, unknown-column 400, and the unchanged nestjsx entry point.
• A go build test generates a full sample service and compiles it with the real Go toolchain.
• npm run build + the go-generator jest suite are green (46 tests; full repo suite 334 green). Verified locally with additional GORM+sqlite runtime tests (eq, or=() via header, order+limit+offset bare windowing, like wildcard, unknown-column 400) — all passing.

Do not merge — left green for review.

🤖 Generated with Claude Code