feat: loadable openclaw channel plugin v1 (agent=account)

Rewritten against the real openclaw v2026.5.7 plugin SDK (generic
third-party channel path): createChannelPluginBase + createChatChannelPlugin
with required capabilities, minimal ChannelSetupAdapter, agent=account
config resolution, attached outbound -> Fabric POST, inbound socket per
account -> runtime.channel.turn (wakeup->admission). Compat notes mark
SDK-coupled seams for future openclaw upgrades. Verified: builds clean,
installs, 'openclaw channels list' -> Fabric installed/configured/enabled.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

src/accounts.ts

@@ -0,0 +1,71 @@
+// agent = openclaw channel account.
+// Config shape:
+//   channels.fabric.centerApiBase = "http://localhost:7001/api"   (shared)
+//   channels.fabric.accounts.<agentId> = { fabricApiKey, centerApiBase? }
+// Each account id IS the openclaw agentId that owns that Fabric identity.
+
+export type FabricAccountConfig = {
+  fabricApiKey?: string;
+  centerApiBase?: string;
+  enabled?: boolean;
+  allowFrom?: string[];
+  dmPolicy?: string;
+};
+
+export type FabricChannelConfig = {
+  centerApiBase?: string;
+  accounts?: Record<string, FabricAccountConfig>;
+  defaultAccount?: string;
+} & FabricAccountConfig;
+
+type Cfg = { channels?: { fabric?: FabricChannelConfig }; [k: string]: unknown };
+
+export type ResolvedFabricAccount = {
+  accountId: string;
+  enabled: boolean;
+  centerApiBase: string;
+  fabricApiKey: string;
+  allowFrom: string[];
+  dmPolicy: string | undefined;
+};
+
+const DEFAULT_CENTER = 'http://localhost:7001/api';
+
+function section(cfg: Cfg): FabricChannelConfig {
+  return cfg.channels?.fabric ?? {};
+}
+
+export function listFabricAccountIds(cfg: Cfg): string[] {
+  const accts = section(cfg).accounts ?? {};
+  const ids = Object.keys(accts);
+  return ids.length ? ids : ['default'];
+}
+
+export function resolveDefaultFabricAccountId(cfg: Cfg): string {
+  const s = section(cfg);
+  if (s.defaultAccount) return s.defaultAccount;
+  const ids = listFabricAccountIds(cfg);
+  return ids[0] ?? 'default';
+}
+
+export function resolveFabricAccount(cfg: Cfg, accountId?: string | null): ResolvedFabricAccount {
+  const s = section(cfg);
+  const id = accountId ?? resolveDefaultFabricAccountId(cfg);
+  const acc = s.accounts?.[id] ?? {};
+  const fabricApiKey = (acc.fabricApiKey ?? '').trim();
+  const centerApiBase = (acc.centerApiBase ?? s.centerApiBase ?? DEFAULT_CENTER).trim();
+  return {
+    accountId: id,
+    enabled: acc.enabled !== false && s.enabled !== false,
+    centerApiBase,
+    fabricApiKey,
+    allowFrom: acc.allowFrom ?? s.allowFrom ?? [],
+    dmPolicy: acc.dmPolicy ?? s.dmPolicy,
+  };
+}
+
+export function listEnabledFabricAccounts(cfg: Cfg): ResolvedFabricAccount[] {
+  return listFabricAccountIds(cfg)
+    .map((id) => resolveFabricAccount(cfg, id))
+    .filter((a) => a.enabled && a.fabricApiKey);
+}