refactor(egress): deduplicate token resolution across backends (PRD 0030)

Extract egress_resolve_token_values_with_provider into bot_bottle/egress.py.
Both docker and smolmachines launch paths now call the shared function
instead of duplicating the forward_host_credentials / CODEX_HOST_CREDENTIAL_TOKEN_REF
resolution block.

Also fixes the host_env: object annotation on smolmachines._resolve_token_env
to the correct dict[str, str].

Closes #118.

tests/unit/test_egress.py

@@ -2,6 +2,7 @@
 resolution (PRD 0017)."""
 
 import unittest
+import unittest.mock
 
 from bot_bottle.egress import (
     CODEX_HOST_CREDENTIAL_TOKEN_REF,
@@ -9,6 +10,7 @@ from bot_bottle.egress import (
     egress_manifest_routes,
     egress_render_routes,
     egress_resolve_token_values,
+    egress_resolve_token_values_with_provider,
     egress_routes_for_bottle,
     egress_token_env_map,
 )
@@ -349,5 +351,64 @@ class TestResolveTokenValues(unittest.TestCase):
         self.assertEqual({}, out)
 
 
+class TestResolveTokenValuesWithProvider(unittest.TestCase):
+    def test_empty_map_returns_empty(self):
+        out = egress_resolve_token_values_with_provider({}, False, {})
+        self.assertEqual({}, out)
+
+    def test_empty_map_with_forward_credentials_returns_empty(self):
+        # forward_host_credentials=True but no slots → no codex call needed.
+        out = egress_resolve_token_values_with_provider({}, True, {})
+        self.assertEqual({}, out)
+
+    def test_manifest_tokens_resolved_without_forward_credentials(self):
+        out = egress_resolve_token_values_with_provider(
+            {"EGRESS_TOKEN_0": "GH_PAT"},
+            False,
+            {"GH_PAT": "ghp_secret"},
+        )
+        self.assertEqual({"EGRESS_TOKEN_0": "ghp_secret"}, out)
+
+    def test_codex_token_slotted_in_when_forward_credentials_and_matching_ref(self):
+        with unittest.mock.patch(
+            "bot_bottle.egress.codex_host_access_token",
+            return_value="codex-access-token",
+        ):
+            out = egress_resolve_token_values_with_provider(
+                {"EGRESS_TOKEN_0": CODEX_HOST_CREDENTIAL_TOKEN_REF},
+                True,
+                {},
+            )
+        self.assertEqual({"EGRESS_TOKEN_0": "codex-access-token"}, out)
+
+    def test_codex_token_not_slotted_when_no_matching_ref(self):
+        # forward_host_credentials=True but no CODEX_HOST_CREDENTIAL_TOKEN_REF
+        # slot in the map → manifest tokens only; Codex token is fetched but
+        # nothing to slot it into.
+        with unittest.mock.patch(
+            "bot_bottle.egress.codex_host_access_token",
+            return_value="codex-access-token",
+        ):
+            out = egress_resolve_token_values_with_provider(
+                {"EGRESS_TOKEN_0": "GH_PAT"},
+                True,
+                {"GH_PAT": "ghp_secret"},
+            )
+        self.assertEqual({"EGRESS_TOKEN_0": "ghp_secret"}, out)
+
+    def test_codex_not_called_when_forward_credentials_false(self):
+        called = []
+        with unittest.mock.patch(
+            "bot_bottle.egress.codex_host_access_token",
+            side_effect=lambda *_: called.append(1) or "tok",
+        ):
+            egress_resolve_token_values_with_provider(
+                {"EGRESS_TOKEN_0": "GH_PAT"},
+                False,
+                {"GH_PAT": "ghp_secret"},
+            )
+        self.assertEqual([], called)
+
+
 if __name__ == "__main__":
     unittest.main()