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/translation-pairing.ts

@@ -2,13 +2,122 @@
  * Pure parsing and structural helpers for the bilingual-document pairing
  * gate. Kept separate from the CLI so corpus discovery and signature behavior
  * can be regression-tested without reading or mutating the repository tree.
+ * Also the one home of the generated-region grammar and the pair-record
+ * primitives, shared by the pairing gate and the region-injecting generators.
  */
 
+import { createHash } from 'node:crypto'
+import { basename } from 'node:path'
 import { fromMarkdown } from 'mdast-util-from-markdown'
 import { gfmFromMarkdown } from 'mdast-util-gfm'
 import { gfm } from 'micromark-extension-gfm'
 import type { Nodes } from 'mdast'
 
+/** Complete opening marker line: `<!-- BEGIN GENERATED <slug> … -->` (slug captured). */
+const GENERATED_REGION_BEGIN_LINE = /^<!-- BEGIN GENERATED (\S+)(?: [^>]*)? -->$/
+/** Complete closing marker line: `<!-- END GENERATED <slug> -->` (slug captured). */
+const GENERATED_REGION_END_LINE = /^<!-- END GENERATED (\S+) -->$/
+/** Loose marker detector: any line that LOOKS like a region marker must parse as one. */
+const GENERATED_REGION_MARKER_HINT = /^<!-- (?:BEGIN|END) GENERATED /
+
+/**
+ * Extract every generated region (markers included) and the document with
+ * those regions removed. Regions are line-delimited: a marker occupies its
+ * whole line, must be a complete well-formed marker, and the closing slug
+ * must match the opener. The stripped form is what "human content" means for
+ * the region-aware pair-record guard.
+ *
+ * @param content - Full Markdown document text.
+ * @returns The regions in document order and the region-free remainder.
+ * @throws Error on an unopened END, unclosed BEGIN, nested BEGIN, malformed
+ *   marker line, or a closing slug that does not match its opener.
+ */
+export function partitionGeneratedRegions(content: string): { regions: string[]; stripped: string } {
+  const lines = content.split('\n')
+  const regions: string[] = []
+  const kept: string[] = []
+  let open: { slug: string; lines: string[] } | null = null
+  for (const line of lines) {
+    const begin = GENERATED_REGION_BEGIN_LINE.exec(line)
+    if (begin?.[1]) {
+      if (open) throw new Error('generated region BEGIN marker nested inside an open region')
+      open = { slug: begin[1], lines: [line] }
+      continue
+    }
+    const end = GENERATED_REGION_END_LINE.exec(line)
+    if (end?.[1]) {
+      if (!open) throw new Error('generated region END marker without a BEGIN')
+      if (end[1] !== open.slug) throw new Error(`generated region END slug '${end[1]}' does not match its BEGIN slug '${open.slug}'`)
+      open.lines.push(line)
+      regions.push(open.lines.join('\n'))
+      open = null
+      continue
+    }
+    if (GENERATED_REGION_MARKER_HINT.test(line)) {
+      throw new Error(`malformed generated region marker line: ${JSON.stringify(line)}`)
+    }
+    if (open) open.lines.push(line)
+    else kept.push(line)
+  }
+  if (open) throw new Error('generated region BEGIN marker without an END')
+  return { regions, stripped: kept.join('\n') }
+}
+
+/**
+ * Full git blob hash of file content (what `git hash-object` prints).
+ * @param content - Exact file bytes.
+ * @returns The 40-hex-digit SHA-1 blob hash.
+ */
+export function blobHash(content: Buffer): string {
+  const hash = createHash('sha1')
+  hash.update(`blob ${content.byteLength}\0`)
+  hash.update(content)
+  return hash.digest('hex')
+}
+
+const PAIR_META_LINE = /^([^:#]+\.md): ([0-9a-f]{40})$/
+
+/**
+ * Parse a `foo.i18n.yaml` consistency record into basename → recorded blob
+ * hash, or undefined when any non-comment line deviates from the exact
+ * `<basename>.md: <40-hex>` shape or repeats a key. Consumers must
+ * additionally require exactly the two expected basenames — a renamed key is
+ * a malformed record, never a silently-missing entry.
+ * @param content - Sidecar file text.
+ * @returns The recorded map, or undefined for a malformed record.
+ */
+export function parsePairMeta(content: string): Map<string, string> | undefined {
+  const out = new Map<string, string>()
+  for (const line of content.split('\n')) {
+    if (line === '' || line.startsWith('#')) continue
+    const match = PAIR_META_LINE.exec(line)
+    if (!match?.[1] || !match[2]) return undefined
+    if (out.has(match[1])) return undefined
+    out.set(match[1], match[2])
+  }
+  return out
+}
+
+/**
+ * Render a `foo.i18n.yaml` consistency record.
+ * @param source - Repo-relative English path.
+ * @param sourceHash - Blob hash of the English side.
+ * @param zh - Repo-relative Chinese path.
+ * @param zhHash - Blob hash of the Chinese side.
+ * @returns The exact sidecar file content.
+ */
+export function renderPairMeta(source: string, sourceHash: string, zh: string, zhHash: string): string {
+  return [
+    '# Bilingual-pair consistency record (docs/i18n/README.md): the git blob hash of each',
+    '# side as of the last confirmed-consistent state. Both languages carry equal authority;',
+    '# after editing either side, bring the other along and re-record with:',
+    `#   pnpm run verify-translation-pairing --write ${source}`,
+    `${basename(source)}: ${sourceHash}`,
+    `${basename(zh)}: ${zhHash}`,
+    '',
+  ].join('\n')
+}
+
 /** Validated shape of `scripts/translation-pairing.manifest.json`. */
 export interface TranslationPairingManifest {
   /** Source documents exempt from pairing because they are generated, instructional, or bilingual by construction. */