fix(telegram): restore named-account DM fallback routing (from #32426)

Rebased and landed contributor work from @chengzhichao-xydt for the
Telegram multi-account DM regression in #32351.

Co-authored-by: Zhichao Cheng <cheng.zhichao@xydigit.com>

src/telegram/bot-message-context.named-account-dm.test.ts

@@ -0,0 +1,147 @@
+import { afterEach, describe, expect, it } from "vitest";
+import { clearRuntimeConfigSnapshot, setRuntimeConfigSnapshot } from "../config/config.js";
+import { buildTelegramMessageContextForTest } from "./bot-message-context.test-harness.js";
+
+describe("buildTelegramMessageContext named-account DM fallback", () => {
+  const baseCfg = {
+    agents: { defaults: { model: "anthropic/claude-opus-4-5", workspace: "/tmp/openclaw" } },
+    channels: { telegram: {} },
+    messages: { groupChat: { mentionPatterns: [] } },
+  };
+
+  afterEach(() => {
+    clearRuntimeConfigSnapshot();
+  });
+
+  it("allows DM through for a named account with no explicit binding", async () => {
+    setRuntimeConfigSnapshot(baseCfg);
+
+    const ctx = await buildTelegramMessageContextForTest({
+      cfg: baseCfg,
+      accountId: "atlas",
+      message: {
+        message_id: 1,
+        chat: { id: 814912386, type: "private" },
+        date: 1700000000,
+        text: "hello",
+        from: { id: 814912386, first_name: "Alice" },
+      },
+    });
+
+    expect(ctx).not.toBeNull();
+    expect(ctx?.route.matchedBy).toBe("default");
+    expect(ctx?.route.accountId).toBe("atlas");
+  });
+
+  it("uses a per-account session key for named-account DMs", async () => {
+    setRuntimeConfigSnapshot(baseCfg);
+
+    const ctx = await buildTelegramMessageContextForTest({
+      cfg: baseCfg,
+      accountId: "atlas",
+      message: {
+        message_id: 1,
+        chat: { id: 814912386, type: "private" },
+        date: 1700000000,
+        text: "hello",
+        from: { id: 814912386, first_name: "Alice" },
+      },
+    });
+
+    expect(ctx?.ctxPayload?.SessionKey).toBe("agent:main:telegram:atlas:direct:814912386");
+  });
+
+  it("isolates sessions between named accounts that share the default agent", async () => {
+    setRuntimeConfigSnapshot(baseCfg);
+
+    const atlas = await buildTelegramMessageContextForTest({
+      cfg: baseCfg,
+      accountId: "atlas",
+      message: {
+        message_id: 1,
+        chat: { id: 814912386, type: "private" },
+        date: 1700000000,
+        text: "hello",
+        from: { id: 814912386, first_name: "Alice" },
+      },
+    });
+    const skynet = await buildTelegramMessageContextForTest({
+      cfg: baseCfg,
+      accountId: "skynet",
+      message: {
+        message_id: 2,
+        chat: { id: 814912386, type: "private" },
+        date: 1700000001,
+        text: "hello",
+        from: { id: 814912386, first_name: "Alice" },
+      },
+    });
+
+    expect(atlas?.ctxPayload?.SessionKey).toBe("agent:main:telegram:atlas:direct:814912386");
+    expect(skynet?.ctxPayload?.SessionKey).toBe("agent:main:telegram:skynet:direct:814912386");
+    expect(atlas?.ctxPayload?.SessionKey).not.toBe(skynet?.ctxPayload?.SessionKey);
+  });
+
+  it("keeps identity-linked peer canonicalization in the named-account fallback path", async () => {
+    const cfg = {
+      ...baseCfg,
+      session: {
+        identityLinks: {
+          "alice-shared": ["telegram:814912386"],
+        },
+      },
+    };
+    setRuntimeConfigSnapshot(cfg);
+
+    const ctx = await buildTelegramMessageContextForTest({
+      cfg,
+      accountId: "atlas",
+      message: {
+        message_id: 1,
+        chat: { id: 999999999, type: "private" },
+        date: 1700000000,
+        text: "hello",
+        from: { id: 814912386, first_name: "Alice" },
+      },
+    });
+
+    expect(ctx?.ctxPayload?.SessionKey).toBe("agent:main:telegram:atlas:direct:alice-shared");
+  });
+
+  it("still drops named-account group messages without an explicit binding", async () => {
+    setRuntimeConfigSnapshot(baseCfg);
+
+    const ctx = await buildTelegramMessageContextForTest({
+      cfg: baseCfg,
+      accountId: "atlas",
+      options: { forceWasMentioned: true },
+      resolveGroupActivation: () => true,
+      message: {
+        message_id: 1,
+        chat: { id: -1001234567890, type: "supergroup", title: "Test Group" },
+        date: 1700000000,
+        text: "@bot hello",
+        from: { id: 814912386, first_name: "Alice" },
+      },
+    });
+
+    expect(ctx).toBeNull();
+  });
+
+  it("does not change the default-account DM session key", async () => {
+    setRuntimeConfigSnapshot(baseCfg);
+
+    const ctx = await buildTelegramMessageContextForTest({
+      cfg: baseCfg,
+      message: {
+        message_id: 1,
+        chat: { id: 42, type: "private" },
+        date: 1700000000,
+        text: "hello",
+        from: { id: 42, first_name: "Alice" },
+      },
+    });
+
+    expect(ctx?.ctxPayload?.SessionKey).toBe("agent:main:main");
+  });
+});

src/telegram/bot-message-context.ts

@@ -39,6 +39,7 @@ import type {
 } from "../config/types.js";
 import { logVerbose, shouldLogVerbose } from "../globals.js";
 import { recordChannelActivity } from "../infra/channel-activity.js";
+import { buildAgentSessionKey } from "../routing/resolve-route.js";
 import { DEFAULT_ACCOUNT_ID, resolveThreadSessionKeys } from "../routing/session-key.js";
 import { resolvePinnedMainDmOwnerFromAllowlist } from "../security/dm-policy-shared.js";
 import { withTelegramApiErrorLogging } from "./api-logging.js";
@@ -55,6 +56,7 @@ import {
   buildTelegramGroupFrom,
   buildTelegramGroupPeerId,
   buildTypingThreadParams,
+  resolveTelegramDirectPeerId,
   resolveTelegramMediaPlaceholder,
   expandTextLinks,
   normalizeForwardedContext,
@@ -208,9 +210,10 @@ export const buildTelegramMessageContext = async ({
   const requiresExplicitAccountBinding = (
     candidate: ReturnType<typeof resolveTelegramConversationRoute>["route"],
   ): boolean => candidate.accountId !== DEFAULT_ACCOUNT_ID && candidate.matchedBy === "default";
-  // Fail closed for named Telegram accounts when route resolution falls back to
-  // default-agent routing. This prevents cross-account DM/session contamination.
-  if (requiresExplicitAccountBinding(route)) {
+  const isNamedAccountFallback = requiresExplicitAccountBinding(route);
+  // Named-account groups still require an explicit binding; DMs get a
+  // per-account fallback session key below to preserve isolation.
+  if (isNamedAccountFallback && isGroup) {
     logInboundDrop({
       log: logVerbose,
       channel: "telegram",
@@ -337,7 +340,22 @@ export const buildTelegramMessageContext = async ({
     return false;
   };
 
-  const baseSessionKey = route.sessionKey;
+  const baseSessionKey = isNamedAccountFallback
+    ? buildAgentSessionKey({
+        agentId: route.agentId,
+        channel: "telegram",
+        accountId: route.accountId,
+        peer: {
+          kind: "direct",
+          id: resolveTelegramDirectPeerId({
+            chatId,
+            senderId,
+          }),
+        },
+        dmScope: "per-account-channel-peer",
+        identityLinks: freshCfg.session?.identityLinks,
+      }).toLowerCase()
+    : route.sessionKey;
   // DMs: use thread suffix for session isolation (works regardless of dmScope)
   const threadKeys =
     dmThreadId != null