fix: preserve ZodObject ergonomics for schema codegen

[bokelley]

Summary

Fixes the remaining Zod codegen DX hardening items from #1979.

• recursively recognizes nested record-only marker unions so object-shaped schemas keep ZodObject helpers
• replaces the shape-fragile schema export regex with a scanner that tolerates = inside type annotations
• rewrites typed string-record/object intersections as object schemas with .catchall(...), preserving both JavaScript ergonomics and additional-property validation
• regenerates affected Zod schemas and adds runtime/type-level regression coverage

Impact

JavaScript and TypeScript adopters can keep using .shape, .extend(), .pick(), and .omit() on object-shaped generated schemas. For typed record intersections such as MediaBuyFeaturesSchema, extra keys still validate against the original record value type.

Validation

• node --test test/generate-zod-object-intersections.test.js
• npm run typecheck
• git diff --check
• pre-push validation: typecheck + library build

Fixes #1979.

[aao-ipr-bot]

LGTM. Follow-ups noted below. The scanner replaces the shape-fragile regex with a proper tokenizer, the .and(z.object()) → .catchall() rewrite preserves wire semantics while restoring ZodObject ergonomics, and the cycle-protected union recursion finally closes the one-level TODO. Right shape.

Things I checked

• Semantic equivalence of the catchall rewrite. Zod v4 treats .catchall(z.boolean()) as the dominant unknown-key strategy; the trailing .passthrough() on the inner object becomes a no-op, and the new chain accepts exactly the set of values the old z.record(z.string(), z.boolean()).and(z.object(...).passthrough()) did. Wire shape unchanged.
• Scanner robustness in findSchemaAssignmentStart (scripts/generate-zod-from-ts.ts:1064-1095). Tracks angleDepth for <>, treats => as one token, and the depth === 0 && angleDepth === 0 guard at line 1085 correctly rejects = inside type annotations like z.ZodType<FactoryOptions<DefaultValue = unknown>> and inside default-arg parens. Template literal types ride on the existing skipQuotedOrRegexLiteral backtick branch (line 842). The targeted test at test/generate-zod-object-intersections.test.js:243-260 exercises the failure mode.
• Cycle protection in collectRedundantRecordUnionSchemaNames (scripts/generate-zod-from-ts.ts:604-647). visiting is per-traversal (fresh new Set() at line 643), names is the persistent accumulator. Mutual cycle A→[B], B→[A] terminates with neither added — visiting hits A while resolving B, returns false, both rolled back. No false positives.
• Else-branch losslessness at scripts/generate-zod-from-ts.ts:467-469. When a typed string record is followed by .and(NOT-z.object), i points one-past the closing ) of .and(...) and the fallback content.substring(recordStart, i) round-trips the original text.
• Changeset and wire impact. Four exported schemas migrate from ZodIntersection to ZodObject + .catchall(): MediaBuyFeaturesSchema, GetBrandIdentitySuccessSchema.fonts, ForecastPointSchema.metrics, GetAdCPCapabilitiesResponseSchema.signals.features. Inferred TS types are equivalent (intersection commutes), runtime validation is equivalent, declared .shape access is now restored. MediaBuyFeaturesSchema correctly drops out of the shape-check exemption list at test/lib/zod-schemas.test.js:645.
• Test export wiring. postProcessRecordIntersections added to __test__ at scripts/generate-zod-from-ts.ts:1728 matches the new postProcessRecordIntersections helper at line 293.

Follow-ups (non-blocking — file as issues)

• Tighten the .catchall(...) rewrite guard at scripts/generate-zod-from-ts.ts:464-466. The current andContent.trimStart().startsWith('z.object(') admits anything that begins with z.object( — including future codegen output like z.object({...}).strict() or z.object({...}).passthrough().refine(...). With a .strict() upstream, the appended .catchall(z.boolean()) would silently override the strict mode and quietly widen validation. No current path produces this, but the assumption is load-bearing. Tighten to require the literal z.object({...}).passthrough() shape (or fall through to the else-branch), and add a regression test that asserts a strict-mode upstream is preserved.
• patch vs minor on the changeset. This intentionally reshapes the runtime class of four exported schemas. Adopters using instanceof z.ZodIntersection or ._def.typeName === 'ZodIntersection' on these schemas will break. Inferred TS types and wire validation are unchanged, so patch is defensible — but it's the borderline call. Worth deciding the rule for this category once and writing it down (probably in CLAUDE.md § "Version Bump Guidelines"). Not blocking this one.
• Test coverage for the else-branch fallback at scripts/generate-zod-from-ts.ts:467-469. The new typed-record tests cover the happy path; an off-by-one in the lossless fallback (typed record followed by .and(SomeNamedSchema)) would not be caught by any test in test/generate-zod-object-intersections.test.js.

Minor nits (non-blocking)

1. Use normalizeSchemaExpression at scripts/generate-zod-from-ts.ts:464. andContent.trimStart().startsWith('z.object(') is a raw substring sniff; the rest of the file routes through normalizeSchemaExpression for whitespace/comment robustness. Matches conventions and folds into the guard-tightening above.

Approving on the strength of the scanner-vs-regex swap plus the recursive cycle-protected union collapse — both close real correctness gaps and not just DX papercuts.

[aao-ipr-bot]

LGTM. Right shape — Record<string,V> & {typed_fields} was always object-shaped on the wire; rewriting it as z.object({...}).catchall(V) matches the type and restores ZodObject ergonomics without weakening the additional-property constraint.

Things I checked

• scripts/generate-zod-from-ts.ts:464-466 — catchall(valueSchema) interpolation uses splitTopLevelCommaList, which is depth- and string-literal-aware. Unions, z.lazy(...), refined schemas, and record-of-record value schemas survive intact.
• scripts/generate-zod-from-ts.ts:1064-1095 — findSchemaAssignmentStart correctly handles default type-parameter values (<T = X>), conditional types, and object-literal defaults inside generics. Replaces the shape-fragile /(?::[^=]+)? = / regex that was tripping on = inside type annotations.
• scripts/generate-zod-from-ts.ts:1230-1259 — isOpaqueRecordMarkerExpression recursion is cycle-safe. Named-schema resolution at :1255 is gated by visiting.has(named) at :1249; union-arm recursion at :1242 threads the same visiting set.
• scripts/generate-zod-from-ts.ts:604-647 — collectRedundantRecordUnionSchemaNames mutual recursion is deterministic. Map iteration is insertion-ordered; findSchemaExportExpressions populates in textual file order; the "add-to-names-as-soon-as-classified" shortcut at :638 is safe because reachability is via recursion before the outer-loop turn.
• src/lib/types/schemas.generated.ts:2141-2174 — GetBrandIdentitySuccessSchema.fonts rewrites correctly: declared primary/secondary validate the typed union, unknown keys validate against the same union via catchall.
• src/lib/types/schemas.generated.ts:3441-3446 — MediaBuyFeaturesSchema now exposes .extend(). Test-allowlist update at test/lib/zod-schemas.test.js:645 reflects this correctly (and the type-test at src/type-tests/zod-schema-ergonomics.type-test.ts:51-54 proves it at compile time).
• __test__ export of postProcessRecordIntersections at scripts/generate-zod-from-ts.ts:1727 — only consumers are the production pipeline at :1638 and the new test harness. No drift.
• Patch changeset is the right type — this is regenerated codegen output. Adopters who consumed MediaBuyFeaturesSchema-and-friends as ZodIntersection now get ZodObject + catchall. Behavior is preserved; ergonomics are additive.

Follow-ups (non-blocking — file as issues)

• Redundant .passthrough() before .catchall() in emitted output. src/lib/types/schemas.generated.ts:2164, :3445, :5529, :7545 all emit .passthrough().catchall(...). .catchall() already governs unknown-key behavior; the .passthrough() is dead weight. Harmless, but a leaner pass would strip .passthrough() immediately preceding .catchall() for cleaner generated output.
• Latent scanner edge case at scripts/generate-zod-from-ts.ts:1084 — a default-typed function-type parameter like <T = (x: number) => string> would prematurely decrement angleDepth on the > after the skipped =>. ts-to-zod doesn't emit this shape today, so unreachable in practice. Worth a short comment near the => handling if future inputs expand.

Safe to merge.