feat(egress): add global log option for full request/response logging

Adds a top-level `log: true` option to the egress config that logs the
full request (method, path, headers, body) and response (status, headers,
body) for every forwarded connection as JSON lines on stderr.

Wire format: `log: true` at the root of routes.yaml, parsed into the new
`Config` dataclass alongside `routes`. The sidecar addon switches from
`self.routes` to `self.config` and writes `_log_request` / `_log_response`
JSON lines when `self.config.log` is set.

Manifest: `egress.log: true` in bottle YAML flows through `EgressConfig.Log`
→ `Egress.prepare()` → `egress_render_routes(..., log=)` → routes.yaml.
`EgressPlan` also carries the flag for introspection.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

tests/unit/test_egress_addon_core.py

@@ -13,6 +13,7 @@ from pathlib import Path
 from urllib.parse import urlsplit
 
 from bot_bottle.egress_addon_core import (
+    Config,
     Decision,
     HeaderMatch,
     MatchEntry,
@@ -21,8 +22,10 @@ from bot_bottle.egress_addon_core import (
     decide,
     evaluate_matches,
     is_git_push_request,
+    load_config,
     load_routes,
     match_route,
+    parse_config,
     parse_routes,
 )
 
@@ -271,6 +274,34 @@ class TestLoadRoutes(unittest.TestCase):
             load_routes("routes:\n\t- host: x\n")
 
 
+# --- load_config / parse_config ------------------------------------------
+
+
+class TestLoadConfig(unittest.TestCase):
+    def test_log_defaults_to_false(self):
+        cfg = load_config('routes:\n  - host: "api.example"\n')
+        self.assertFalse(cfg.log)
+        self.assertEqual(1, len(cfg.routes))
+
+    def test_log_true_parsed(self):
+        cfg = load_config('log: true\nroutes:\n  - host: "api.example"\n')
+        self.assertTrue(cfg.log)
+        self.assertEqual(1, len(cfg.routes))
+
+    def test_log_false_explicit(self):
+        cfg = load_config('log: false\nroutes:\n  - host: "api.example"\n')
+        self.assertFalse(cfg.log)
+
+    def test_log_non_bool_rejected(self):
+        with self.assertRaises(ValueError):
+            load_config('log: "yes"\nroutes: []\n')
+
+    def test_routes_accessible_via_config(self):
+        cfg = load_config('routes:\n  - host: "x.example"\n')
+        self.assertIsInstance(cfg, Config)
+        self.assertEqual("x.example", cfg.routes[0].host)
+
+
 # --- evaluate_matches ---------------------------------------------------