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

bot_bottle/orchestrator/store.py

@@ -0,0 +1,48 @@
+"""State store interface + an in-memory implementation.
+
+The orchestrator persists one `RunRecord` per forge-targeted issue. At
+runtime `bootstrap` supplies an adapter over bot-bottle's
+`SqliteForgeStateStore`; the in-memory store here backs tests and a
+`--no-bot-bottle` dry mode.
+"""
+
+from __future__ import annotations
+
+from typing import Protocol
+
+from .model import RunRecord
+
+
+class StateStore(Protocol):
+    """Thin CRUD surface. Mirrors bot-bottle's `ForgeStateStore` so the
+    bootstrap adapter is a straight pass-through."""
+
+    def upsert(self, record: RunRecord) -> None: ...
+
+    def get(self, owner: str, repo: str, issue_number: int) -> RunRecord | None: ...
+
+    def delete(self, owner: str, repo: str, issue_number: int) -> None: ...
+
+    def all(self) -> list[RunRecord]: ...
+
+
+class InMemoryStateStore:
+    """Dict-backed `StateStore`, keyed by (owner, repo, issue_number)."""
+
+    def __init__(self) -> None:
+        self._by_key: dict[tuple[str, str, int], RunRecord] = {}
+
+    def upsert(self, record: RunRecord) -> None:
+        self._by_key[(record.owner, record.repo, record.issue_number)] = record
+
+    def get(self, owner: str, repo: str, issue_number: int) -> RunRecord | None:
+        return self._by_key.get((owner, repo, issue_number))
+
+    def delete(self, owner: str, repo: str, issue_number: int) -> None:
+        self._by_key.pop((owner, repo, issue_number), None)
+
+    def all(self) -> list[RunRecord]:
+        return sorted(
+            self._by_key.values(),
+            key=lambda r: (r.owner, r.repo, r.issue_number),
+        )