docs(gururmm): record dashboard beta-first channel + memory

- wiki/projects/gururmm.md: beta-first dashboard channels (rmm-beta) + wiring
- .claude/memory: feedback_dashboard_beta_first + index line
- bump guru-rmm submodule pointer to the beta-channel commit

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

.claude/memory/MEMORY.md

@@ -65,6 +65,7 @@
 ### GuruRMM
 - [GuruRMM operational rules](feedback_gururmm.md) — Six rules: (1) RMM dev = Mike, never Howard (368/0 commits); GuruScan is Howard's. (2) Agent parity Win+Linux+macOS in same change. (3) Builds via Gitea webhook pipeline only, never SSH. (4) #bot-alerts only for client/ticket impact, skip internal infra/dev. (5) Identify agents by IP, not by reconning candidates. (6) UNC paths in user_session need [char]92 — literals get halved.
 - [Build channel default = beta](feedback_gururmm_build_channel_default.md) — New agent builds must be tagged BETA by default (stable = explicit promote re-tag); distinct from agents defaulting to the stable CHANNEL (correct). Fixed build-windows/linux.sh 2026-06-01; macOS already correct. Enables beta-first canary.
+- [Dashboard beta-first deploy](feedback_dashboard_beta_first.md) — Dashboard auto-builds to rmm-beta.azcomputerguru.com on push; prod (rmm.azcomputerguru.com) is explicit promote-only via promote-dashboard.sh --confirm. Never hand-rsync prod. One artifact, nginx sub_filter BETA banner. Stood up 2026-06-02.
 
 ### Cascades
 - [Cascades operational rules](feedback_cascades.md) — Two active rules: (1) folder redirection (fdeploy) needs subfolders PRE-CREATED before first logon or it caches a failure forever; recovery via fix-shell-redirect.ps1. (2) ALWAYS ask which security group(s) a new user goes into — never auto-derive from OU.