feat: add bootstrap domain (models, setup modules, planning)

- Profile, BootstrapAction, BootstrapPlan models
- Setup modules: hostname, locale, shell, ssh-keygen, runcmd
- Bootstrap planning with ordered phases and env validation

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

tests/test_domain_bootstrap_modules.py

@@ -0,0 +1,73 @@
+"""Tests for bootstrap setup modules."""
+
+from flow.domain.bootstrap.modules import (
+    HostnameModule,
+    LocaleModule,
+    RuncmdModule,
+    ShellModule,
+    SSHKeygenModule,
+)
+
+
+class TestHostnameModule:
+    def test_describe(self):
+        m = HostnameModule(hostname="my-host")
+        assert isinstance(m.describe(), str)
+        assert "my-host" in m.describe()
+
+    def test_plan(self):
+        m = HostnameModule(hostname="my-host")
+        cmds = m.plan()
+        assert len(cmds) > 0
+        assert any("my-host" in c for c in cmds)
+
+
+class TestLocaleModule:
+    def test_describe(self):
+        m = LocaleModule(locale="en_US.UTF-8")
+        assert isinstance(m.describe(), str)
+        assert "en_US.UTF-8" in m.describe()
+
+    def test_plan(self):
+        m = LocaleModule(locale="en_US.UTF-8")
+        cmds = m.plan()
+        assert len(cmds) > 0
+
+
+class TestShellModule:
+    def test_describe(self):
+        m = ShellModule(shell="zsh")
+        assert isinstance(m.describe(), str)
+        assert "zsh" in m.describe()
+
+    def test_plan(self):
+        m = ShellModule(shell="zsh")
+        cmds = m.plan()
+        assert len(cmds) > 0
+
+
+class TestSSHKeygenModule:
+    def test_describe(self):
+        m = SSHKeygenModule(keys=[{"path": "~/.ssh/id_ed25519"}])
+        assert isinstance(m.describe(), str)
+        assert "1" in m.describe()
+
+    def test_plan(self):
+        m = SSHKeygenModule(keys=[
+            {"path": "~/.ssh/id_ed25519", "type": "ed25519", "comment": "me@host"},
+        ])
+        cmds = m.plan()
+        assert len(cmds) == 1
+        assert "ssh-keygen" in cmds[0]
+
+
+class TestRuncmdModule:
+    def test_describe(self):
+        m = RuncmdModule(commands=["echo a", "echo b", "echo c"])
+        assert isinstance(m.describe(), str)
+        assert "3" in m.describe()
+
+    def test_plan(self):
+        m = RuncmdModule(commands=["echo hello"])
+        cmds = m.plan()
+        assert cmds == ["echo hello"]