docs: generate each subsystem's cordis surface into its own page; delete the flat catalogs

Rebuild of the region machinery (PR3) on the post-#904 Typert projection:
renderPageRegion/renderInheritedPage live in dsh-typert-generator beside the
projection; scripts/gen-cordis-catalog.ts owns the curated SERVICE_PAGE /
EVENT_SCOPE_PAGE / SERVICE_WALK_EXEMPTIONS / LINK_MAP partition (fail-loud in
both directions, with the independent Context-merge scan backstopping the
projection's blind spot), spliceRegion, and the guarded pair auto-record.
docs/cordis-catalog/ is deleted: the flat events/services catalogs dissolve
into per-page regions and docs/cordis-catalog/core moves to docs/cordis-api/
with the inherited tier as its own generated page. The partition absorbs the
post-regrouping surface: ctx.typert → invariants.md, ctx.directoryPicker →
workspace.md, skills/* events → skills.md, and the four launcher-provided tui
accessor values join the named exemptions.

scripts/cordis-walk.ts

@@ -1,7 +1,39 @@
-/** Locate the Cordis module merge used by the vendored core API projector. */
+/**
+ * AST helpers shared by the Cordis generators: locate the Cordis module merge
+ * in a source file and enumerate the `interface Context` keys it declares.
+ * The vendored core API projector consumes the merge body; the per-subsystem
+ * region generator's exhaustiveness backstop consumes the key scan.
+ */
 
+import { globSync, readFileSync } from 'node:fs'
+import { resolve, sep } from 'node:path'
 import ts from 'typescript'
 
+/**
+ * Parse every file matching `pattern` (repo-relative, sorted, `/`-normalized)
+ * that textually mentions `interface Context`, yielding each file's cordis
+ * module-merge body. Files without a merge are skipped.
+ * @param scanRoot - Repository root the pattern is resolved against.
+ * @param pattern - Glob selecting the TypeScript files to scan.
+ * @returns One entry per file with a cordis module merge, in path order.
+ */
+export function contextMergeFiles(
+  scanRoot: string,
+  pattern: string,
+): { rel: string; sf: ts.SourceFile; text: string; body: ts.ModuleBlock }[] {
+  const out: { rel: string; sf: ts.SourceFile; text: string; body: ts.ModuleBlock }[] = []
+  for (const rel of globSync(pattern, { cwd: scanRoot }).map(s => s.split(sep).join('/')).sort()) {
+    const abs = resolve(scanRoot, rel)
+    const text = readFileSync(abs, 'utf8')
+    if (!text.includes('interface Context')) continue
+    const sf = ts.createSourceFile(abs, text, ts.ScriptTarget.Latest, true)
+    const body = cordisModuleBody(sf)
+    if (!body) continue
+    out.push({ rel, sf, text, body })
+  }
+  return out
+}
+
 /** The body of the cordis module merge in `sf`: `declare module 'cordis'`
  * (harness packages) or `declare module './context.ts'` (vendor core), or
  * null when the file has neither. */
@@ -13,3 +45,22 @@ export function cordisModuleBody(sf: ts.SourceFile): ts.ModuleBlock | null {
   }
   return null
 }
+
+/**
+ * Every `key: Type` property a `declare module 'cordis'` Context merge
+ * declares in one module body.
+ * @param body - The cordis module augmentation block.
+ * @param sf - Owning source file (for text extraction).
+ * @returns key → declared type-name text, in declaration order.
+ */
+export function contextKeyMap(body: ts.ModuleBlock, sf: ts.SourceFile): Map<string, string> {
+  const keyToType = new Map<string, string>()
+  for (const stmt of body.statements) {
+    if (!ts.isInterfaceDeclaration(stmt) || stmt.name.text !== 'Context') continue
+    for (const member of stmt.members) {
+      if (!ts.isPropertySignature(member) || !member.type) continue
+      keyToType.set(member.name.getText(sf), member.type.getText(sf))
+    }
+  }
+  return keyToType
+}