feat(claude): spawn hosted sessions under the bound account's CLAUDE_CONFIG_DIR (T-484)

The load-bearing piece of the multi-account epic (T-476): a bound workspace's
hosted claude now spawns with CLAUDE_CONFIG_DIR set to that account's dir, so
it runs under the bound account end-to-end. Every hosted session (primary /
secondary / fork / teammate) inherits it — the orchestrator already routes all
spawns through agentBootstrap.

- New pure resolver claudeConfigDirForWorkspace(cwd, boundConfigDir, env):
  bound account dir > parent CLAUDE_CONFIG_DIR (respect the launcher) > null
  (Claude defaults to ~/.claude). The registry is injected as a plain lookup
  so agent_bootstrap stays Flutter-free (its tests run under `dart test`).
- agentBootstrap merges CLAUDE_CONFIG_DIR BEFORE base, so an explicit
  SpawnSpec.env override still wins (override > binding > parent > unset); the
  key is omitted entirely when the resolver returns null.
- Orchestrator carries an optional AccountRegistry; the claude extension builds
  it from ctx.settings. Null in tests → no injection (unchanged behaviour).

No way to SET a binding yet (that's the CLI T-480 / settings UI T-482), so no
changelog entry — the mechanism is in place, the surface lands next. Unit tests
cover the resolver's four states and the envDelta precedence.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

lib/builtin/claude/src/agent_bootstrap.dart

@@ -74,6 +74,21 @@ Map<String, String> agentEnvDelta({required String workspaceRoot, required Strin
   return delta;
 }
 
+/// Resolve the `CLAUDE_CONFIG_DIR` a session in [cwd] should run under (T-484,
+/// epic T-476): the bound account's dir when the workspace is bound, else the
+/// parent's `CLAUDE_CONFIG_DIR` when the launcher already set one, else null
+/// (Claude defaults to `~/.claude`).
+///
+/// Pure: the AccountRegistry is injected as a plain [boundConfigDir] lookup
+/// (workspace → bound config dir, or null) so this stays Flutter-free — the
+/// registry itself lives behind a ChangeNotifier the orchestrator owns.
+String? claudeConfigDirForWorkspace({required String cwd, required String? Function(String cwd) boundConfigDir, required Map<String, String> env}) {
+  final bound = boundConfigDir(cwd);
+  if (bound != null && bound.isNotEmpty) return bound;
+  final inherited = env['CLAUDE_CONFIG_DIR'];
+  return (inherited != null && inherited.isNotEmpty) ? inherited : null;
+}
+
 /// Locate the directory to prepend to a hosted agent's PATH so `clide`
 /// resolves (T-215). Returns null when `clide` is ALREADY on [currentPath]
 /// (the installed case — T-211 drops it in `~/.local/bin`, normally already
@@ -107,7 +122,7 @@ class AgentBootstrap {
 /// env (usually null → inherit clide's). The returned [AgentBootstrap.extraArgs]
 /// carries the context note; team callers append their own preamble and the
 /// orchestrator merges both into one `--append-system-prompt`.
-AgentBootstrap agentBootstrap(String workspaceRoot, {Map<String, String>? base}) {
+AgentBootstrap agentBootstrap(String workspaceRoot, {Map<String, String>? base, String? Function(String cwd)? boundConfigDir}) {
   final home = Platform.environment['HOME'];
   // The login-shell-resolved PATH (T-439) so a hosted claude — and the tools it
   // shells out to — find user-installed components on a desktop launch, not just
@@ -120,7 +135,12 @@ AgentBootstrap agentBootstrap(String workspaceRoot, {Map<String, String>? base})
   ];
   final cliDir = resolveClideCliDir(currentPath: currentPath, candidateDirs: candidates, isExecutableFile: _isExecutableFile);
   final delta = agentEnvDelta(workspaceRoot: workspaceRoot, socketPath: workspaceSocketPath(workspaceRoot), currentPath: currentPath, clideCliDir: cliDir);
-  return AgentBootstrap(envDelta: {...?base, ...delta}, extraArgs: ['--allowedTools', clideBashAllowRule]);
+  // Per-repo Claude account (T-484): a bound workspace runs claude under that
+  // account's CLAUDE_CONFIG_DIR. Spread BEFORE base so an explicit per-call
+  // SpawnSpec.env override still wins (precedence: override > binding > parent
+  // env > unset); omitted entirely when there's nothing to set.
+  final configDir = claudeConfigDirForWorkspace(cwd: workspaceRoot, boundConfigDir: boundConfigDir ?? (_) => null, env: Platform.environment);
+  return AgentBootstrap(envDelta: {'CLAUDE_CONFIG_DIR': ?configDir, ...?base, ...delta}, extraArgs: ['--allowedTools', clideBashAllowRule]);
 }
 
 bool _isExecutableFile(String path) {

lib/builtin/claude/src/extension.dart

@@ -2,6 +2,7 @@ import 'dart:async';
 import 'dart:io';
 
 import 'package:clide/clide.dart';
+import 'package:clide/builtin/claude/src/account_registry.dart';
 import 'package:clide/builtin/claude/src/activity_cluster.dart' show foldLevelFromName, kActivityFoldLevelKey, nextFoldLevel;
 import 'package:clide/builtin/claude/src/claude_config.dart';
 import 'package:clide/builtin/claude/src/claude_status.dart' show nextSafePermissionMode;
@@ -467,8 +468,9 @@ class ClaudeExtension extends ClideExtension {
     }
 
     // The clide-managed session set (T-169). Panes spawn/bind through it so a
-    // session outlives its pane and is shared across surfaces.
-    _orchestrator = ClaudeSessionOrchestrator();
+    // session outlives its pane and is shared across surfaces. The account
+    // registry (T-476) lets a bound workspace spawn under its own Claude account.
+    _orchestrator = ClaudeSessionOrchestrator(accountRegistry: AccountRegistry(ctx.settings));
     activeSessionOrchestrator = _orchestrator;
 
     // An in-place workspace switch (Open Project/Folder) must not leave the

lib/builtin/claude/src/session_orchestrator.dart

@@ -15,6 +15,7 @@ import 'dart:async';
 import 'dart:convert';
 import 'dart:io';
 
+import 'package:clide/builtin/claude/src/account_registry.dart';
 import 'package:clide/builtin/claude/src/agent_bootstrap.dart';
 import 'package:clide/builtin/claude/src/conversation_controller.dart';
 import 'package:clide/builtin/claude/src/session_naming.dart';
@@ -152,10 +153,15 @@ class ManagedSession {
 ClaudeSessionOrchestrator? activeSessionOrchestrator;
 
 class ClaudeSessionOrchestrator extends ChangeNotifier {
-  ClaudeSessionOrchestrator({ProcessFactory? processFactory}) : _factory = processFactory ?? _spawnClaude {
+  ClaudeSessionOrchestrator({ProcessFactory? processFactory, this.accountRegistry}) : _factory = processFactory ?? _spawnClaude {
     _chatModel = TeamChatModel(broker: broker, sessionResolver: (name) => byMemberName(name)?.session);
   }
 
+  /// Per-repo Claude account bindings (epic T-476). When a workspace is bound,
+  /// its hosted sessions spawn under that account's CLAUDE_CONFIG_DIR (T-484).
+  /// Null in tests / when no registry is wired → no injection.
+  final AccountRegistry? accountRegistry;
+
   final ProcessFactory _factory;
   final _sessions = <String, ManagedSession>{};
 
@@ -244,7 +250,7 @@ class ClaudeSessionOrchestrator extends ChangeNotifier {
       mcpServers.add(TeamMcpServer(broker: broker, memberId: spec.id));
       preambles.add(_teamSystemPrompt(name, spec.role));
     }
-    final bootstrap = agentBootstrap(spec.cwd, base: spec.env);
+    final bootstrap = agentBootstrap(spec.cwd, base: spec.env, boundConfigDir: (cwd) => accountRegistry?.accountForWorkspace(cwd)?.dir);
     sessionArgs = [
       '--append-system-prompt',
       preambles.join('\n\n'),