feat: add session.identityLinks for cross-platform DM session linking (#1033)

Co-authored-by: Shadow <shadow@clawd.bot>

docs/gateway/configuration.md

@@ -2269,6 +2269,9 @@ Controls session scoping, idle expiry, reset triggers, and where the session sto
   session: {
     scope: "per-sender",
     dmScope: "main",
+    identityLinks: {
+      alice: ["telegram:123456789", "discord:987654321012345678"]
+    },
     idleMinutes: 60,
     resetTriggers: ["/new", "/reset"],
     // Default is already per-agent under ~/.clawdbot/agents/<agentId>/sessions/sessions.json
@@ -2297,6 +2300,8 @@ Fields:
   - `main`: all DMs share the main session for continuity.
   - `per-peer`: isolate DMs by sender id across channels.
   - `per-channel-peer`: isolate DMs per channel + sender (recommended for multi-user inboxes).
+- `identityLinks`: map canonical ids to provider-prefixed peers so the same person shares a DM session across channels when using `per-peer` or `per-channel-peer`.
+  - Example: `alice: ["telegram:123456789", "discord:987654321012345678"]`.
 - `agentToAgent.maxPingPongTurns`: max reply-back turns between requester/target (0–5, default 5).
 - `sendPolicy.default`: `allow` or `deny` fallback when no rule matches.
 - `sendPolicy.rules[]`: match by `channel`, `chatType` (`direct|group|room`), or `keyPrefix` (e.g. `cron:`). First deny wins; otherwise allow.

docs/gateway/security.md

@@ -133,7 +133,7 @@ By default, Clawdbot routes **all DMs into the main session** so your assistant
 }
 ```
 
-This prevents cross-user context leakage while keeping group chats isolated. See [Session Management](/concepts/session) and [Configuration](/gateway/configuration).
+This prevents cross-user context leakage while keeping group chats isolated. If the same person contacts you on multiple channels, use `session.identityLinks` to collapse those DM sessions into one canonical identity. See [Session Management](/concepts/session) and [Configuration](/gateway/configuration).
 
 ## Allowlists (DM + groups) — terminology