feat: type validation issue kinds as ValidationIssueKind

docs/api.md

@@ -31,7 +31,7 @@ see [architecture.md](architecture.md#information-flow) for that flow.
 
 `ValidationResult.ruleViolations` carries each violation's effective `severity` (`error`, `warning` or `info`). Only `error` severity violations should be treated as failures.
 
-`nodeIssues(result)` gathers every result about a node into one map per node: schema, duplicate id, broken link, hierarchy, rule, gated and unresolved content link issues, each keyed by a composite id such as `rule:<id>` and carrying its `kind`, `message` and `severity`. Read `severity` rather than deriving it from `kind`. Pass `{ includeGated }` as validation ran, so a gated node's note says whether its rules were evaluated. Rule violations without a node and parse issues stay in their own parts of the result. `validateFile` returns one node's map as `issues`.
+`nodeIssues(result)` gathers every result about a node into one map per node: schema, duplicate id, broken link, hierarchy, rule, gated and unresolved content link issues, each keyed by a composite id such as `rule:<id>` and carrying its `kind`, `message` and `severity`. `kind` is a `ValidationIssueKind`, and `VALIDATION_ISSUE_KINDS` lists every kind at runtime. Read `severity` rather than deriving it from `kind`. Pass `{ includeGated }` as validation ran, so a gated node's note says whether its rules were evaluated. Rule violations without a node and parse issues stay in their own parts of the result. `validateFile` returns one node's map as `issues`.
 
 Each `ValidationResult` entry about a node carries its `nodeId`, and, where the entry is tied to a location, an optional `source` (`{ file, line?, column? }`). `duplicateErrors` lists a `sources` location for each node that shares the `id`. See [Validation results and nodes](concepts.md#validation-results-and-nodes).
 

src/api.ts

@@ -83,6 +83,8 @@ export type {
   SpaceContext,
   UnresolvedRef,
   ValidateFileOutput,
+  ValidationIssueKind,
 } from './types';
+export { VALIDATION_ISSUE_KINDS } from './types';
 export type { ValidationResult } from './validate';
 export { nodeIssues, validateFile, validateSpace } from './validate';

src/types.ts

@@ -274,9 +274,22 @@ export type SpaceContext = {
   configDir: string;
 };
 
+/** The checks a validation issue can come from. */
+export const VALIDATION_ISSUE_KINDS = [
+  'schema',
+  'duplicate',
+  'broken-link',
+  'hierarchy',
+  'rule',
+  'gated',
+  'content-link',
+] as const;
+
+export type ValidationIssueKind = (typeof VALIDATION_ISSUE_KINDS)[number];
+
 export interface FileValidationIssue {
-  /** The check it came from: `schema`, `duplicate`, `broken-link`, `hierarchy`, `rule`, `gated` or `content-link`. */
-  kind: string;
+  /** The check it came from. */
+  kind: ValidationIssueKind;
   message: string;
   /** How serious the issue is; consumers read it rather than infer it from `kind`. */
   severity: RuleSeverity;