feat: fold bot-bottle-orchestrator into bot_bottle/orchestrator subpackage

Moves the orchestrator into bot_bottle/orchestrator/ so one install gets
everything. Entry point is now `python -m bot_bottle.orchestrator run`.

- Add bot_bottle/orchestrator/ with all 14 modules (verbatim move; internal
  imports were already relative, so no changes inside orchestrator modules)
- Rewrite bootstrap.py: remove the lazy bot_bottle import guard, use direct
  relative imports from ..contrib.*
- Add bot_bottle/contrib/forge/base.py: ScopedForge (read-anywhere / write-scoped)
- Add bot_bottle/contrib/gitea/client.py: GiteaClient + GiteaForge (urllib.request only)
- Add bot_bottle/contrib/gitea/forge_state.py: ForgeState + SqliteForgeStateStore
- Add tests/unit/orchestrator/ (82 tests: 63 migrated + 19 new for contrib modules)

Closes #321

tests/unit/orchestrator/test_forge_state.py

@@ -0,0 +1,75 @@
+"""Unit: ForgeState + SqliteForgeStateStore."""
+
+from __future__ import annotations
+
+import unittest
+
+from bot_bottle.contrib.gitea.forge_state import ForgeState, SqliteForgeStateStore
+
+
+def _state(**kw: object) -> ForgeState:
+    defaults: dict[str, object] = dict(
+        owner="alice", repo="myrepo", issue_number=1,
+        slug="impl-alice-myrepo-1", agent_name="impl",
+    )
+    defaults.update(kw)
+    return ForgeState(**defaults)  # type: ignore[arg-type]
+
+
+class ForgeStateStoreTest(unittest.TestCase):
+    def setUp(self):
+        self.store = SqliteForgeStateStore(None)
+
+    def test_upsert_and_get(self):
+        s = _state()
+        self.store.upsert(s)
+        got = self.store.get("alice", "myrepo", 1)
+        assert got is not None
+        self.assertEqual("impl-alice-myrepo-1", got.slug)
+        self.assertEqual("impl", got.agent_name)
+
+    def test_get_missing(self):
+        self.assertIsNone(self.store.get("alice", "myrepo", 99))
+
+    def test_upsert_replaces(self):
+        self.store.upsert(_state(status="running"))
+        self.store.upsert(_state(status="frozen"))
+        got = self.store.get("alice", "myrepo", 1)
+        assert got is not None
+        self.assertEqual("frozen", got.status)
+
+    def test_delete(self):
+        self.store.upsert(_state())
+        self.store.delete("alice", "myrepo", 1)
+        self.assertIsNone(self.store.get("alice", "myrepo", 1))
+
+    def test_delete_missing_no_error(self):
+        self.store.delete("alice", "myrepo", 99)
+
+    def test_all_sorted(self):
+        self.store.upsert(_state(owner="z", issue_number=2))
+        self.store.upsert(_state(owner="a", issue_number=1))
+        rows = self.store.all()
+        self.assertEqual(("a", "z"), (rows[0].owner, rows[1].owner))
+
+    def test_bottle_names_roundtrip(self):
+        self.store.upsert(_state(bottle_names=["claude", "dev"]))
+        got = self.store.get("alice", "myrepo", 1)
+        assert got is not None
+        self.assertEqual(["claude", "dev"], got.bottle_names)
+
+    def test_pr_number_none_roundtrip(self):
+        self.store.upsert(_state(pr_number=None))
+        got = self.store.get("alice", "myrepo", 1)
+        assert got is not None
+        self.assertIsNone(got.pr_number)
+
+    def test_pr_number_int_roundtrip(self):
+        self.store.upsert(_state(pr_number=42))
+        got = self.store.get("alice", "myrepo", 1)
+        assert got is not None
+        self.assertEqual(42, got.pr_number)
+
+
+if __name__ == "__main__":
+    unittest.main()