refactor(#1277): T1 — decouple agent-install-check + git-base-branch from the core spine (#1280)

First leaf-migration tranche of epic #1267 (after T0 #1268). Migrate the
via-core callers of the two leaves T0 created to import from the leaf
modules directly, and stop core re-exporting their symbols:
- checkAgentsInstalled: docs.cts, verify.cts, init.cts -> agent-install-check.cjs
- gitWorktreeInfoInternal: init.cts -> git-base-branch.cjs
- getAgentsDir had no external via-core caller (internal to the leaf)

core no longer re-exports getAgentsDir / checkAgentsInstalled /
gitWorktreeInfoInternal; the now-unused agent-install-check + git-base-branch
requires are dropped from core; the shim-identity assertions for these are
deleted (behaviour tests retained). Convergence lint stays green (0 new).
No behaviour change.

Closes #1277

Co-authored-by: Claude Opus 4.8 <noreply@anthropic.com>

src/core.cts

@@ -51,10 +51,6 @@ const {
 import phaseLocatorModule = require('./phase-locator.cjs');
 const { searchPhaseInDir, findPhaseInternal, getArchivedPhaseDirs } = phaseLocatorModule;
 import { findProjectRoot } from './project-root.cjs';
-// eslint-disable-next-line @typescript-eslint/no-require-imports
-import agentInstallCheck = require('./agent-install-check.cjs');
-// eslint-disable-next-line @typescript-eslint/no-require-imports
-import gitBaseBranch = require('./git-base-branch.cjs');
 
 // ─── Config Loader Module (extracted from core, ADR-857 phase 2e / #885) ─────
 // eslint-disable-next-line @typescript-eslint/no-require-imports
@@ -123,8 +119,7 @@ const {
 
 // ─── Agent installation validation (#1371) ───────────────────────────────────
 // getAgentsDir and checkAgentsInstalled moved to agent-install-check.cjs (T0 #1268).
-// The destructured bindings above (from agentInstallCheck) make them available to
-// core-internal callers; core.cjs re-exports both symbols by reference for back-compat.
+// Re-exports removed in T1 (#1277); callers import directly from agent-install-check.cjs.
 
 // ─── Model alias resolution ───────────────────────────────────────────────────
 // RUNTIME_OVERRIDE_TIERS, _warnedConfigKeys, _warnUnknownProfileOverrides, and
@@ -192,7 +187,6 @@ export = {
   resolveModelPolicy,
   KNOWN_PROVIDERS,
   pathExistsInternal,
-  gitWorktreeInfoInternal: gitBaseBranch.gitWorktreeInfoInternal,
   generateSlugInternal,
   getMilestoneInfo,
   getMilestonePhaseFilter,
@@ -219,8 +213,6 @@ export = {
   filterSummaryFiles,
   getPhaseFileStats,
   readSubdirectories,
-  getAgentsDir: agentInstallCheck.getAgentsDir,
-  checkAgentsInstalled: agentInstallCheck.checkAgentsInstalled,
   timeAgo,
   pruneOrphanedWorktrees: worktreeSafety.pruneOrphanedWorktrees,
   inspectWorktreeHealth,

src/docs.cts

@@ -14,7 +14,10 @@ import fs from 'node:fs';
 import path from 'node:path';
 // eslint-disable-next-line @typescript-eslint/no-require-imports
 import core = require('./core.cjs');
-const { output, loadConfig, resolveModelInternal, pathExistsInternal, toPosixPath, checkAgentsInstalled } = core;
+const { output, loadConfig, resolveModelInternal, pathExistsInternal, toPosixPath } = core;
+// eslint-disable-next-line @typescript-eslint/no-require-imports
+import agentInstallCheck = require('./agent-install-check.cjs');
+const { checkAgentsInstalled } = agentInstallCheck;
 import { platformReadSync } from './shell-command-projection.cjs';
 
 // ─── Constants ────────────────────────────────────────────────────────────────

src/init.cts

@@ -25,6 +25,12 @@ import { validatePath, loadTrustedGlobalRoots } from './security.cjs';
 import { getGlobalSkillDir, getGlobalSkillDisplayPath, getGlobalSkillsBase } from './runtime-homes.cjs';
 // eslint-disable-next-line @typescript-eslint/no-require-imports -- frontmatter.cjs is an export= CommonJS module
 import frontmatterMod = require('./frontmatter.cjs');
+// eslint-disable-next-line @typescript-eslint/no-require-imports -- agent-install-check.cjs is an export= CommonJS module
+import agentInstallCheck = require('./agent-install-check.cjs');
+const { checkAgentsInstalled } = agentInstallCheck;
+// eslint-disable-next-line @typescript-eslint/no-require-imports -- git-base-branch.cjs is an export= CommonJS module
+import gitBaseBranch = require('./git-base-branch.cjs');
+const { gitWorktreeInfoInternal } = gitBaseBranch;
 
 const {
   loadConfig,
@@ -34,7 +40,6 @@ const {
   findPhaseInternal,
   getRoadmapPhaseInternal,
   pathExistsInternal,
-  gitWorktreeInfoInternal,
   generateSlugInternal,
   getMilestoneInfo,
   getMilestonePhaseFilter,
@@ -44,7 +49,6 @@ const {
   toPosixPath,
   output,
   error,
-  checkAgentsInstalled,
   phaseTokenMatches,
 } = core;
 

src/verify.cts

@@ -28,6 +28,9 @@ import { PACKAGE_NAME } from './package-identity.cjs';
 import { formatGsdSlash, resolveRuntime } from './runtime-slash.cjs';
 import { detectSchemaFiles, checkSchemaDrift } from './schema-detect.cjs';
 import { isCanonicalPlanningFile } from './artifacts.cjs';
+// eslint-disable-next-line @typescript-eslint/no-require-imports -- agent-install-check.cjs is an export= CommonJS module
+import agentInstallCheck = require('./agent-install-check.cjs');
+const { checkAgentsInstalled } = agentInstallCheck;
 
 const {
   loadConfig,
@@ -40,7 +43,6 @@ const {
   extractCurrentMilestone,
   output,
   error,
-  checkAgentsInstalled,
   CONFIG_DEFAULTS,
   inspectWorktreeHealth,
 } = core;