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/commands.md

@@ -97,3 +97,89 @@ interface ParsedCommand {
   readonly rawInput: 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="ctxcommands--commandservice"></a>
+
+### `ctx.commands` — `CommandService`
+
+Human-command registry. Plain-context definitions are global; definitions registered through a command-injected child of an agent context shadow globals for that agent.
+
+```ts cordis-catalog
+/**
+ * Register a global or calling-agent-scoped command.
+ * @param definition - discovery metadata and direct UI handler.
+ * @returns the exact effect disposer that unregisters this definition.
+ */
+register(definition: CommandDefinition): () => void
+
+/**
+ * List the effective immutable command descriptors for one agent.
+ * @param agent - exact receiving agent and scoped-layer key.
+ * @returns name-sorted descriptors after scoped shadowing.
+ */
+list(agent: Agent): readonly CommandDescriptor[]
+
+/**
+ * Resolve one effective command definition.
+ * @param agent - exact receiving agent and scoped-layer key.
+ * @param name - command name without a slash.
+ * @returns the scoped shadow or global definition.
+ */
+find(agent: Agent, name: string): CommandDefinition | undefined
+
+/**
+ * Parse and execute a known command without sending it to the model.
+ *
+ * A resolved command's lifecycle is logged: `command/run` is appended
+ * before the handler is invoked and `command/done` after settlement (a
+ * thrown or aborted handler settles as `kind: 'error'`). Both are direct
+ * log-only appends — no turn wraps them, and persistence drains them at
+ * ordinary checkpoints. Admission misses (syntax or unknown name) log
+ * nothing — they never entered a handler. A `command/run` append failure
+ * fails the execution loud; a `command/done` append failure on the
+ * handler-failure path is contained so the handler's own error stays the
+ * reported failure.
+ *
+ * @param agent - exact receiving agent.
+ * @param line - complete slash-command line.
+ * @param signal - cancellation signal owned by the UI request.
+ * @returns the settled execution (result + lifecycle pairing id), or
+ *   `undefined` when syntax or name does not resolve.
+ */
+async execute( agent: Agent, line: string, signal: AbortSignal, ): Promise<CommandExecution | undefined>
+```
+
+Types: [Agent](core.md)
+
+Source: [`packages/interaction/commands/src/index.ts:305`](../../packages/interaction/commands/src/index.ts)
+
+<a id="commands-events"></a>
+
+### `commands/*` events
+
+<a id="commandschange--emit"></a>
+
+#### `commands/change` — emit
+
+A command was registered or unregistered. This is an unfiltered registry notification because a global or scoped change may affect any UI view. Observer failures are contained and cannot veto the registry mutation.
+
+```ts cordis-catalog
+/**
+ * A command was registered or unregistered. This is an unfiltered registry
+ * notification because a global or scoped change may affect any UI view.
+ * Observer failures are contained and cannot veto the registry mutation.
+ * @mode emit
+ */
+'commands/change'(): void
+```
+
+Source: [`packages/interaction/commands/src/index.ts:172`](../../packages/interaction/commands/src/index.ts)
+<!-- END GENERATED cordis-surface -->