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/contrib/gitea/forge_state.py

@@ -0,0 +1,137 @@
+"""Forge state persistence for the orchestrator (PRD prd-new: fold orchestrator).
+
+`ForgeState` is a dataclass that mirrors the orchestrator's `RunRecord`
+field-for-field, held here so the store implementation is in bot-bottle
+where the Gitea contrib lives.
+
+`SqliteForgeStateStore` backs it with a single SQLite table. The DB path
+is optional; passing `None` uses `:memory:` (useful for tests and status
+commands that don't need persistence).
+"""
+
+from __future__ import annotations
+
+import json
+import sqlite3
+from dataclasses import dataclass, field
+from pathlib import Path
+
+
+@dataclass
+class ForgeState:
+    """Persisted state for one forge-targeted issue's bottle lifecycle."""
+
+    owner: str
+    repo: str
+    issue_number: int
+    slug: str
+    agent_name: str
+    bottle_names: list[str] = field(default_factory=list)
+    backend_name: str = ""
+    agent_git_user: str = ""
+    pr_number: int | None = None
+    status: str = ""
+    last_checkin_at: str = ""
+
+
+_DDL = """
+CREATE TABLE IF NOT EXISTS forge_state (
+    owner        TEXT NOT NULL,
+    repo         TEXT NOT NULL,
+    issue_number INTEGER NOT NULL,
+    slug         TEXT NOT NULL,
+    agent_name   TEXT NOT NULL,
+    bottle_names TEXT NOT NULL DEFAULT '[]',
+    backend_name TEXT NOT NULL DEFAULT '',
+    agent_git_user TEXT NOT NULL DEFAULT '',
+    pr_number    INTEGER,
+    status       TEXT NOT NULL DEFAULT '',
+    last_checkin_at TEXT NOT NULL DEFAULT '',
+    PRIMARY KEY (owner, repo, issue_number)
+)
+"""
+
+
+class SqliteForgeStateStore:
+    """SQLite-backed `ForgeState` store.
+
+    Thread-safety: a single connection is used; callers that share a
+    store across threads must serialise access externally.
+    """
+
+    def __init__(self, db_path: Path | None) -> None:
+        path = str(db_path) if db_path is not None else ":memory:"
+        self._conn = sqlite3.connect(path, check_same_thread=False)
+        self._conn.row_factory = sqlite3.Row
+        self._conn.execute(_DDL)
+        self._conn.commit()
+
+    def upsert(self, state: ForgeState) -> None:
+        self._conn.execute(
+            """
+            INSERT INTO forge_state
+                (owner, repo, issue_number, slug, agent_name,
+                 bottle_names, backend_name, agent_git_user,
+                 pr_number, status, last_checkin_at)
+            VALUES (?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?)
+            ON CONFLICT(owner, repo, issue_number) DO UPDATE SET
+                slug            = excluded.slug,
+                agent_name      = excluded.agent_name,
+                bottle_names    = excluded.bottle_names,
+                backend_name    = excluded.backend_name,
+                agent_git_user  = excluded.agent_git_user,
+                pr_number       = excluded.pr_number,
+                status          = excluded.status,
+                last_checkin_at = excluded.last_checkin_at
+            """,
+            (
+                state.owner,
+                state.repo,
+                state.issue_number,
+                state.slug,
+                state.agent_name,
+                json.dumps(state.bottle_names),
+                state.backend_name,
+                state.agent_git_user,
+                state.pr_number,
+                state.status,
+                state.last_checkin_at,
+            ),
+        )
+        self._conn.commit()
+
+    def get(self, owner: str, repo: str, issue_number: int) -> ForgeState | None:
+        row = self._conn.execute(
+            "SELECT * FROM forge_state WHERE owner=? AND repo=? AND issue_number=?",
+            (owner, repo, issue_number),
+        ).fetchone()
+        return _row_to_state(row) if row is not None else None
+
+    def delete(self, owner: str, repo: str, issue_number: int) -> None:
+        self._conn.execute(
+            "DELETE FROM forge_state WHERE owner=? AND repo=? AND issue_number=?",
+            (owner, repo, issue_number),
+        )
+        self._conn.commit()
+
+    def all(self) -> list[ForgeState]:
+        rows = self._conn.execute(
+            "SELECT * FROM forge_state ORDER BY owner, repo, issue_number"
+        ).fetchall()
+        return [_row_to_state(r) for r in rows]
+
+
+def _row_to_state(row: sqlite3.Row) -> ForgeState:
+    return ForgeState(
+        owner=row["owner"],
+        repo=row["repo"],
+        issue_number=row["issue_number"],
+        slug=row["slug"],
+        agent_name=row["agent_name"],
+        bottle_names=json.loads(row["bottle_names"]),
+        backend_name=row["backend_name"],
+        agent_git_user=row["agent_git_user"],
+        pr_number=row["pr_number"],
+        status=row["status"],
+        last_checkin_at=row["last_checkin_at"],
+    )