refactor: remove SERVICE_AGENT_TYPE legacy constant

SERVICE_AGENT_TYPE was always 'claude-code' in the unified service,
making it a misleading constant. Each group already has its own
agentType field.

- Removed SERVICE_AGENT_TYPE from config.ts
- Session functions now accept agentType parameter (default: 'claude-code')
- Task scheduler uses task-level agent_type for token rotation decisions
- All fallback defaults changed to 'claude-code' literal
- Logging uses 'unified' instead of the misleading type

src/agent-runner.ts

@@ -75,7 +75,10 @@ export async function runAgentProcess(
   // ── Reviewer container mode ─────────────────────────────────────
   // Reviewers always run inside a Docker container with read-only source
   // mount for kernel-level write protection. Docker is required.
-  if (envOverrides?.EJCLAW_REVIEWER_RUNTIME === '1' || envOverrides?.EJCLAW_ARBITER_RUNTIME === '1') {
+  if (
+    envOverrides?.EJCLAW_REVIEWER_RUNTIME === '1' ||
+    envOverrides?.EJCLAW_ARBITER_RUNTIME === '1'
+  ) {
     const ownerWorkspaceDir =
       envOverrides?.EJCLAW_WORK_DIR || group.workDir || process.cwd();
 
@@ -83,7 +86,10 @@ export async function runAgentProcess(
     // so the Claude SDK inside the container has platform & paired room prompts.
     const sessionDir = envOverrides?.CLAUDE_CONFIG_DIR;
     if (sessionDir) {
-      const containerRole = envOverrides?.EJCLAW_ARBITER_RUNTIME === '1' ? 'arbiter' as const : 'reviewer' as const;
+      const containerRole =
+        envOverrides?.EJCLAW_ARBITER_RUNTIME === '1'
+          ? ('arbiter' as const)
+          : ('reviewer' as const);
       prepareContainerSessionEnvironment({
         sessionDir,
         chatJid: input.chatJid,