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.

docs/subsystems/system-prompt.md

@@ -76,3 +76,113 @@ interface PromptContext {
   readonly text: string | ((context: AssembleContext) => string)
 }
 ```
+
+<!-- BEGIN GENERATED cordis-surface (gen-cordis-catalog.ts) — do not edit between markers -->
+
+<a id="cordis-surface"></a>
+
+## Cordis surface
+
+Generated from source by `scripts/gen-cordis-catalog.ts` (verified fresh by `pnpm run verify-cordis-catalog` in doc-sync; regenerate with `pnpm run gen-cordis-catalog`) — this section is byte-identical in both language sides of the page. Signature blocks use a `ts cordis-catalog` fence and keep the original source JSDoc; dispatch modes are defined in the [primer](../cordis-primer.md#dispatch-modes), and the framework-inherited `ctx` surface lives in [cordis-api/inherited.md](../cordis-api/inherited.md).
+
+<a id="ctxsystemprompt--systemprompt"></a>
+
+### `ctx.systemPrompt` — `SystemPrompt`
+
+Registry service for the prompt inputs assembled before each model step.
+
+```ts cordis-catalog
+/**
+ * Register an ordered prompt section in the calling context's scope. A scoped
+ * section shadows a global section with the same name; duplicates within one
+ * layer and non-finite orders throw. Registration and disposal emit
+ * `system-prompt/change`.
+ * @param section - the section to register.
+ * @returns the exact Cordis effect disposer.
+ */
+section(section: PromptSection): () => void
+
+/**
+ * Register ordered dynamic context in the calling context's scope. Scoped
+ * entries shadow global entries with the same name.
+ * @param context - the context contribution to register.
+ * @returns the exact Cordis effect disposer.
+ */
+context(context: PromptContext): () => void
+
+/**
+ * Register a tool-schema provider in the calling context's scope. Global and
+ * matching scoped providers both contribute; returning the reserved
+ * {@link TOOL_ORDER_REST} name makes assembly fail.
+ * @param provider - evaluated for each assembly with its context.
+ * @returns the exact Cordis effect disposer.
+ */
+tools(provider: (context: AssembleContext) => ToolProviderResult): () => void
+
+/**
+ * Register a prompt variable in the calling context's scope. Scoped values
+ * shadow globals; invalid or duplicate names throw. A provider may return
+ * `undefined`, but rendering a section that references that value then fails.
+ * @param name - the `[a-z][a-z0-9_]*` reference name.
+ * @param provider - evaluated for each assembly.
+ * @returns the exact Cordis effect disposer.
+ */
+variable(name: string, provider: (context: AssembleContext) => string | undefined): () => void
+
+/**
+ * Assemble global and scoped providers, detach tool parameters, apply
+ * canonical ordering, then run the assembly waterfall. Scoped sections and
+ * variables shadow globals; the returned waterfall value is authoritative.
+ * @param context - the optional scope and plugin-defined assembly fields.
+ * @returns the authoritative post-waterfall assembly.
+ */
+async assemble(context: AssembleContext = {}): Promise<PromptAssembly>
+```
+
+Source: [`packages/core/system-prompt/src/index.ts:314`](../../packages/core/system-prompt/src/index.ts)
+
+<a id="system-prompt-events"></a>
+
+### `system-prompt/*` events
+
+<a id="system-promptassemble--waterfall"></a>
+
+#### `system-prompt/assemble` — waterfall
+
+Expert waterfall over the assembled sections, contexts, tools, and variables. Scope-filtered dispatch (`@deepseek-ai/dsh-scope`): scoped listeners receive only that scope's assemblies. The returned value is authoritative. A supplied signal controls only this explicit assembly request and must not be retained to control later turns.
+
+```ts cordis-catalog
+/**
+ * Expert waterfall over the assembled sections, contexts, tools, and variables.
+ * Scope-filtered dispatch (`@deepseek-ai/dsh-scope`): scoped listeners
+ * receive only that scope's assemblies. The returned value is authoritative.
+ * A supplied signal controls only this explicit assembly request and must not
+ * be retained to control later turns.
+ * @param assembly - the mutable assembly built from registered providers.
+ * @param context - the caller's per-assembly context.
+ * @mode waterfall
+ */
+'system-prompt/assemble'(this: Scoped<SystemPrompt>, assembly: PromptAssembly, context: AssembleContext, next: () => Promise<PromptAssembly>): Promise<PromptAssembly>
+```
+
+Types: [Scoped](scope.md)
+
+Source: [`packages/core/system-prompt/src/index.ts:29`](../../packages/core/system-prompt/src/index.ts)
+
+<a id="system-promptchange--emit"></a>
+
+#### `system-prompt/change` — emit
+
+Emitted when any prompt provider changes. This registry notification is unfiltered because a global change affects every scope.
+
+```ts cordis-catalog
+/**
+ * Emitted when any prompt provider changes. This registry notification is
+ * unfiltered because a global change affects every scope.
+ * @mode emit
+ */
+'system-prompt/change'(): void
+```
+
+Source: [`packages/core/system-prompt/src/index.ts:35`](../../packages/core/system-prompt/src/index.ts)
+<!-- END GENERATED cordis-surface -->