#9106: fix(matrix): override DM detection for rooms in groups config

## Summary Rooms with exactly 2 members (user + bot) are incorrectly classified as DMs by the member-count heuristic in `direct.ts`, even when explicitly configured in `channels.matrix.groups`. This causes them to route to the user's DM session instead of the intended room-specific agent. Fixes #7718 ## Changes **`extensions/matrix/src/matrix/monitor/handler.ts`** - Move `resolveMatrixRoomConfig()` before the DM classification check - If the room is present in the groups config, override `isDirectMessage` to `false` - This ensures rooms in the config always receive group treatment regardless of member count ## Testing Deployed to production with 3 private rooms (2 members each: user + bot) configured in `channels.matrix.groups`. Confirmed: - Rooms route to their configured agents via `bindings` (not the DM agent) - `requireMention: false` works correctly on group-overridden rooms - Standard DMs still route correctly to per-user agents <!-- greptile_comment --> <h2>Greptile Overview</h2> <h3>Greptile Summary</h3> This change moves `resolveMatrixRoomConfig()` earlier in the Matrix inbound handler and uses it to override direct-message detection so that rooms explicitly configured under `channels.matrix.groups` are always treated as group rooms, avoiding the 2-member heuristic in `direct.ts`. One issue to fix before merge: the override currently triggers for any resolved config, including `"*"` wildcard matches. Because wildcard configs can be used to disable/deny rooms by default, this can cause true DMs to be reclassified as rooms and dropped by the room allowlist/disabled checks, breaking DM routing when a wildcard entry exists. <h3>Confidence Score: 2/5</h3> - This PR should not merge until the DM override condition is narrowed to avoid wildcard group configs breaking DM routing. - The change correctly addresses misclassification of configured 2-member rooms, but the new override (`roomConfigInfo?.config`) also applies to wildcard matches, which can reclassify real DMs as rooms and then drop them via the room allowlist/disabled logic. - extensions/matrix/src/matrix/monitor/handler.ts <!-- greptile_other_comments_section --> <!-- /greptile_comment -->