refactor(templates): separate identity and SOUL responsibilities

Move all behavioral instructions out of identity.md into SOUL.md so that
each file has a single clear purpose:

- identity.md: capability facts only (runtime, workspace, format hints,
  tool guidance, untrusted content warning)
- SOUL.md: behavioral rules (name, personality, execution rules)

The "Act, don't narrate" rule is refined into layered behavior: act
immediately on single-step tasks, plan first for multi-step tasks. This
eliminates the contradiction where identity said "never end with a plan"
but user SOUL.md said "always plan first".

tests/agent/test_context_prompt_cache.py

@@ -149,16 +149,39 @@ def test_partial_dream_processing_shows_only_remainder(tmp_path) -> None:
 
 
 def test_execution_rules_in_system_prompt(tmp_path) -> None:
-    """New execution rules should appear in the system prompt."""
+    """Execution rules should appear in the system prompt via default SOUL.md."""
+    from nanobot.utils.helpers import sync_workspace_templates
+
     workspace = _make_workspace(tmp_path)
+    sync_workspace_templates(workspace, silent=True)
     builder = ContextBuilder(workspace)
 
     prompt = builder.build_system_prompt()
-    assert "Act, don't narrate" in prompt
+    assert "single-step tasks" in prompt
+    assert "multi-step tasks" in prompt
     assert "Read before you write" in prompt
     assert "verify the result" in prompt
 
 
+def test_identity_has_no_behavioral_instructions(tmp_path) -> None:
+    """Identity template should not contain behavioral rules or hardcoded name."""
+    workspace = _make_workspace(tmp_path)
+    builder = ContextBuilder(workspace)
+
+    identity = builder._get_identity(channel=None)
+    assert "You are nanobot" not in identity
+    assert "Act, don't narrate" not in identity
+    assert "Execution Rules" not in identity
+
+
+def test_default_soul_template_contains_execution_rules() -> None:
+    """Default SOUL.md template must contain execution rules with act/plan layering."""
+    soul = (pkg_files("nanobot") / "templates" / "SOUL.md").read_text(encoding="utf-8")
+    assert "## Execution Rules" in soul
+    assert "single-step tasks" in soul
+    assert "multi-step tasks" in soul
+
+
 def test_channel_format_hint_telegram(tmp_path) -> None:
     """Telegram channel should get messaging-app format hint."""
     workspace = _make_workspace(tmp_path)