migrate consuming stacks to ESO + remove k8s-dashboard static token

Phase 9: ExternalSecret migration across 26 stacks:

Fully migrated (vault data source removed, ESO delivers secrets):
- speedtest, shadowsocks, wealthfolio, plotting-book, f1-stream, tandoor
- n8n, dawarich, diun, netbox, onlyoffice, tuya-bridge
- hackmd (ESO template for DB URL), health (ESO template for DB URL)
- trading-bot (ESO template for DATABASE_URL + 7 secret env vars)
- forgejo (removed unused vault data source)

Partially migrated (vault kept for plan-time, ESO added for runtime):
- immich, linkwarden, nextcloud, paperless-ngx (jsondecode for homepage)
- claude-memory, rybbit, url, webhook_handler (plan-time in locals/jobs)
- woodpecker, openclaw, resume (plan-time in helm values/jobs/modules)

17 stacks unchanged (all plan-time: homepage annotations, configmaps,
module inputs) — vault data source works with OIDC auth.

Phase 17a: Remove k8s-dashboard static admin token secret.
Users now get tokens via: vault write kubernetes/creds/dashboard-admin

stacks/hackmd/providers.tf

@@ -13,12 +13,6 @@ variable "kube_config_path" {
   default = "~/.kube/config"
 }
 
-variable "vault_root_token" {
-  type      = string
-  sensitive = true
-  default   = ""
-}
-
 provider "kubernetes" {
   config_path = var.kube_config_path
 }
@@ -31,6 +25,5 @@ provider "helm" {
 
 provider "vault" {
   address          = "https://vault.viktorbarzin.me"
-  token            = var.vault_root_token
   skip_child_token = true
 }