refactor: unify peer kind to ChatType, rename dm to direct (#11881)

* fix: use .js extension for ESM imports of RoutePeerKind

The imports incorrectly used .ts extension which doesn't resolve
with moduleResolution: NodeNext. Changed to .js and added 'type'
import modifier.

* fix tsconfig

* refactor: unify peer kind to ChatType, rename dm to direct

- Replace RoutePeerKind with ChatType throughout codebase
- Change 'dm' literal values to 'direct' in routing/session keys
- Keep backward compat: normalizeChatType accepts 'dm' -> 'direct'
- Add ChatType export to plugin-sdk, deprecate RoutePeerKind
- Update session key parsing to accept both 'dm' and 'direct' markers
- Update all channel monitors and extensions to use ChatType

BREAKING CHANGE: Session keys now use 'direct' instead of 'dm'.
Existing 'dm' keys still work via backward compat layer.

* fix tests

* test: update session key expectations for dmdirect migration

- Fix test expectations to expect :direct: in generated output
- Add explicit backward compat test for normalizeChatType('dm')
- Keep input test data with :dm: keys to verify backward compat

* fix: accept legacy 'dm' in session key parsing for backward compat

getDmHistoryLimitFromSessionKey now accepts both :dm: and :direct:
to ensure old session keys continue to work correctly.

* test: add explicit backward compat tests for dmdirect migration

- session-key.test.ts: verify both :dm: and :direct: keys are valid
- getDmHistoryLimitFromSessionKey: verify both formats work

* feat: backward compat for resetByType.dm config key

* test: skip unix-path Nix tests on Windows

src/discord/monitor/message-handler.inbound-contract.test.ts

@@ -87,12 +87,12 @@ describe("discord processDiscordMessage inbound contract", () => {
       guildInfo: null,
       guildSlug: "",
       channelConfig: null,
-      baseSessionKey: "agent:main:discord:dm:u1",
+      baseSessionKey: "agent:main:discord:direct:u1",
       route: {
         agentId: "main",
         channel: "discord",
         accountId: "default",
-        sessionKey: "agent:main:discord:dm:u1",
+        sessionKey: "agent:main:discord:direct:u1",
         mainSessionKey: "agent:main:main",
         // oxlint-disable-next-line typescript/no-explicit-any
       } as any,

src/discord/monitor/message-handler.preflight.ts

@@ -224,7 +224,7 @@ export async function preflightDiscordMessage(
     accountId: params.accountId,
     guildId: params.data.guild_id ?? undefined,
     peer: {
-      kind: isDirectMessage ? "dm" : isGroupDm ? "group" : "channel",
+      kind: isDirectMessage ? "direct" : isGroupDm ? "group" : "channel",
       id: isDirectMessage ? author.id : message.channelId,
     },
     // Pass parent peer for thread binding inheritance

src/discord/monitor/native-command.ts

@@ -736,7 +736,7 @@ async function dispatchDiscordCommandInteraction(params: {
     accountId,
     guildId: interaction.guild?.id ?? undefined,
     peer: {
-      kind: isDirectMessage ? "dm" : isGroupDm ? "group" : "channel",
+      kind: isDirectMessage ? "direct" : isGroupDm ? "group" : "channel",
       id: isDirectMessage ? user.id : channelId,
     },
     parentPeer: threadParentId ? { kind: "channel", id: threadParentId } : undefined,