Summary

Adds a new dmScope option: per-account-channel-peer that includes the accountId in session keys, enabling isolated sessions per channel account.

Problem

When running multiple Telegram bots (or other channel accounts) pointing to the same agent, all DMs from the same user merge into a single session. This breaks:

• Separation of concerns (work/personal/tasks contexts mixing)
• Parallelism (can't have concurrent conversations across bots)
• Privacy (sensitive context leaks between bots)

Solution

New session key format that includes accountId:

• Before: agent:main:telegram:dm:123456
• After: agent:main:telegram:tasks:dm:123456

Configuration

{
  "session": {
    "dmScope": "per-account-channel-peer"
  }
}

Changes

• src/config/types.base.ts — Add new scope to DmScope type
• src/config/zod-schema.session.ts — Add to zod schema
• src/routing/session-key.ts — Include accountId in key generation
• src/routing/resolve-route.ts — Pass accountId through routing
• src/infra/outbound/outbound-session.ts — Extract accountId from delivery context
• src/routing/resolve-route.test.ts — Add tests (13/13 passing)

Testing

npm test -- src/routing/resolve-route.test.ts

All 13 tests pass, including 2 new tests for per-account-channel-peer routing.

Closes #3094