Gate JSDoc completeness on every package export

New doc-sync gate verify-export-jsdoc walks every module-level exported
name under packages/*/*/src and requires description prose everywhere,
plus @param per parameter and @returns on non-void annotated returns for
function-like exports, public class methods, properties, and accessors.
The parsing + check helpers move out of gen-cordis-catalog.ts into a
shared scripts/jsdoc.ts so 'documented' means one thing on both gated
surfaces.

Deliberate exemptions (documented in the RFC): heritage-declared class
members (the seam declaration is the doc's one home — the one checker
query in an otherwise pure-AST walk), cordis plugin-protocol slots
(name/inject/reusable/Config/apply, top-level and static), constructors,
overload implementations, declare-module augmentation bodies, and
re-export statements (checked at the defining module).

The 203 under-documented exports the gate found at adoption are filled
in this change, so the gate lands green; generated catalogs/graphs are
regenerated for the shifted line pointers.

RFC: docs/rfc/implemented/process/2026-07-06-export-surface-jsdoc-gate.md

packages/core/session/src/surface.ts

@@ -29,6 +29,8 @@ const SURFACE_EVENT_TYPES = new Set<string>([
  * surface-eligible event that is MISSING its mandatory marker (e.g. validating
  * a seed/load log); use {@link isSurfaceEvent} to narrow to a fully-formed
  * {@link SurfaceEvent} with `surfaceOp` present.
+ * @param type - the event type string to test.
+ * @returns true when the type is one of the five message-producing types.
  */
 export function isSurfaceEligibleType(type: string): boolean {
   return SURFACE_EVENT_TYPES.has(type)
@@ -38,6 +40,8 @@ export function isSurfaceEligibleType(type: string): boolean {
  * Narrow a {@link SessionEvent} to {@link SurfaceEvent}: checks that the
  * event's `type` is surface-eligible AND that `surfaceOp` is present.
  * The narrowed type has mandatory {@link SurfaceOp}.
+ * @param event - the event to narrow.
+ * @returns true when the event is surface-eligible and carries its `surfaceOp` marker.
  */
 export function isSurfaceEvent(event: SessionEvent): event is SurfaceEvent {
   if (!SURFACE_EVENT_TYPES.has(event.type)) return false