chore: remove backend code nothing references

Found with knip (exports, types, class members) and confirmed by a text
search of src, test, scripts and packages before each removal.

- Per-CLI get<Cli>NotFoundMessage() (nine of them) with their message
  constants: missingCliMessage() builds that text from the registry now.
- Registry leftovers: renderCliCommand, asCliId, cliIds, isCliRunnable,
  createCliResolverForTest, profileExists, and two name lists that only
  repeated schema enums.
- A task-description cache in Session that was written on every chunk of
  terminal output (one regex pass per line) and never read since the
  subagent watcher takes descriptions from transcripts. The cache module,
  its pattern and both parse methods go with it.
- Session.parentAgentId / childAgentIds: never set by anything, so the two
  optional SessionState fields were never on the wire.
- Unreferenced methods on TmuxManager (pipe-pane pair, syncMouseMode),
  RespawnController, StateStore.recoverFromBackup (load() already falls
  back to the .bak file), TeamWatcher, SseStreamManager and the AI
  checkers' getErrorVerdict.
- updateCaseEnvVars: the settings.local.json env path that envOverrides
  replaced.
- Re-exports in the utils, cli-registry, routes and prompts barrels that
  no importer used, and unused test helpers (MockStateStore, the mobile
  throttle helpers and others).

Eight mobile tests imported the WebServer type from a path that does not
exist (../src instead of ../../src); type-only, so nothing failed.

Co-Authored-By: Claude Fable 5.2 <noreply@anthropic.com>

src/config/cli-registry/argv.ts

@@ -26,7 +26,7 @@
  * @module config/cli-registry/argv
  */
 
-import type { ArgSpec, CliEntry, CliLaunch, Cond, EngineValue, ParamSpec, QuoteStyle } from './types.js';
+import type { ArgSpec, CliLaunch, Cond, EngineValue, ParamSpec, QuoteStyle } from './types.js';
 import { matchesPattern } from './patterns.js';
 import { SAFE_BARE_TOKEN } from './patterns.js';
 
@@ -178,13 +178,3 @@ export function renderLaunch(
 
   return rendered.join(' || ');
 }
-
-/** Convenience: render an entry's launch command straight from a `CliEntry`. */
-export function renderCliCommand(
-  entry: CliEntry,
-  params: ParamValues,
-  engineValues: EngineValues,
-  gatesPassed?: ReadonlySet<string>
-): string {
-  return renderLaunch(entry.launch, params, engineValues, gatesPassed);
-}

src/config/cli-registry/index.ts

@@ -3,59 +3,4 @@
  * @module config/cli-registry
  */
 
-export type {
-  ArgSpec,
-  CliCapabilities,
-  CliCredStore,
-  CliDiscovery,
-  CliEntry,
-  CliEnv,
-  CliId,
-  CliIdentityProbe,
-  CliLaunch,
-  CliOverlays,
-  CliRegistryFile,
-  CliVariant,
-  CliVersionProbe,
-  Cond,
-  EngineValue,
-  ParamSpec,
-  QuoteStyle,
-} from './types.js';
-export {
-  matchesPattern,
-  TOKEN_PATTERNS,
-  SAFE_BARE_TOKEN,
-  compileVersionRegex,
-  MAX_VERSION_OUTPUT,
-} from './patterns.js';
-export type { TokenPattern } from './patterns.js';
-export { renderLaunch, renderCliCommand } from './argv.js';
-export type { EngineValues, ParamValues } from './argv.js';
-export { CliEntrySchema } from './schema.js';
-export type { ValidatedCliEntry } from './schema.js';
-export { STOCK_CLIS } from './stock.js';
-export {
-  asCliId,
-  cliIds,
-  enabledCliIds,
-  enabledClis,
-  getCli,
-  listClis,
-  loadCliRegistry,
-  reloadCliRegistry,
-  resolveInstallCommandForPlatform,
-  resolveRegistry,
-} from './registry.js';
-export type { LoadResult } from './registry.js';
-export {
-  COMPOSER_ANCHOR_KINDS,
-  isKnownLauncherProfile,
-  isKnownPredictProfile,
-  isKnownSetenvProfile,
-  LAUNCHER_PROFILE_NAMES,
-  PREDICT_PROFILES,
-  SETENV_PROFILE_NAMES,
-  TRANSCRIPT_READER_NAMES,
-} from './profiles.js';
-export type { LauncherProfileName, SetenvProfileName } from './profiles.js';
+export { enabledCliIds, getCli } from './registry.js';

src/config/cli-registry/profiles.ts

@@ -76,16 +76,6 @@ export const SETENV_PROFILE_NAMES = [
 export type LauncherProfileName = (typeof LAUNCHER_PROFILE_NAMES)[number];
 export type SetenvProfileName = (typeof SETENV_PROFILE_NAMES)[number];
 
-/**
- * Transcript readers, selected via `capabilities.transcript`. Unlike the profile registries
- * above this one is closed over the schema enum itself rather than an open string, since
- * transcript format is a small, genuinely fixed set — see CliCapabilities['transcript'].
- */
-export const TRANSCRIPT_READER_NAMES = ['claude-jsonl', 'codex-rollout', 'deepseek-zstd', 'none'] as const;
-
-/** Composer-row finders, selected via `capabilities.echo.anchor.kind`. Also schema-closed. */
-export const COMPOSER_ANCHOR_KINDS = ['glyph', 'cursor', 'none'] as const;
-
 /** True when `name` is a predictive-echo profile this build actually implements. */
 export function isKnownPredictProfile(name: string | undefined): boolean {
   return name !== undefined && Object.prototype.hasOwnProperty.call(PREDICT_PROFILES, name);

src/config/cli-registry/registry.ts

@@ -32,18 +32,10 @@
 
 import { existsSync, readFileSync, renameSync, statSync } from 'node:fs';
 import { dataPath } from '../instance.js';
-import type { CliEntry, CliId, CliRegistryFile } from './types.js';
+import type { CliEntry, CliRegistryFile } from './types.js';
 import { CliEntrySchema } from './schema.js';
 import { STOCK_CLIS } from './stock.js';
 
-/** Construct a validated CliId. Throws if `raw` is not a well-formed id — call at API boundaries. */
-export function asCliId(raw: string): CliId {
-  if (!/^[a-z][a-z0-9-]{0,23}$/.test(raw)) {
-    throw new Error(`invalid CLI id: ${JSON.stringify(raw)}`);
-  }
-  return raw as CliId;
-}
-
 function filePath(): string {
   return dataPath('clis.json');
 }
@@ -227,10 +219,6 @@ export function getCli(id: string): CliEntry | undefined {
   return listClis().find((e) => (e.id as string) === id);
 }
 
-export function cliIds(): string[] {
-  return listClis().map((e) => e.id as string);
-}
-
 /** Every enabled entry's id, in registry order. */
 export function enabledCliIds(): string[] {
   return enabledClis().map((e) => e.id as string);

src/config/cli-registry/schema.ts

@@ -817,5 +817,3 @@ export const CliEntrySchema = z
       });
     }
   });
-
-export type ValidatedCliEntry = z.infer<typeof CliEntrySchema>;