Analytics: Environment Filtering — Documentation: dashboard docs, configuration reference, and data-reset notice

Summary

Document the new environment selector for dashboard users, the new per-customer configuration for Platform/support, and publish the data-reset customer notice — the last of these must land before the release, not after, per the epic's own acceptance criteria.

Parent epic: #37349
Spike: #37107
Depends on: final naming/behavior decisions from the dotCMS-core (config endpoint contract) and Dashboard (selector UX) sub-tasks, for the user-facing docs to be accurate. The data-reset notice specifically should be drafted early and does not need to wait on those.

Background

The epic's acceptance criteria explicitly call out: "Data-reset notice and the 'production numbers will change' note land before the release, not after." This is a hard release gate, not a nice-to-have — customers must know in advance that:

• Their existing Content Analytics data is being dropped as part of this rollout (per the epic's reset decision — no backfill, no migration of historical numbers).
• Their dashboard numbers will restart from zero (or from whatever point the reset lands) once the new schema is live.
• A new environment selector will appear, defaulting to their current environment, letting them view other environments' data going forward.

Scope

• Dashboard user-facing docs: what the environment selector does, default behavior (defaults to current environment), what "no selection changed" means (today's blended-view behavior, unchanged), how to switch to viewing another environment.
• Configuration reference: DOT_ANALYTICS_ENVIRONMENT / DOT_ANALYTICS_AVAILABLE_ENVIRONMENTS — what they are, how Platform curates the available-environments list per customer, what happens if a customer's list drifts out of sync (self-heals, logs a warning, never breaks the dropdown).
• Data-reset customer notice: explain the ClickHouse reset in plain terms, that historical analytics numbers reset at cutover, expected timing, and that this is a one-time event tied to this rollout (not a recurring behavior).

Out of scope

• Internal engineering documentation already covered by the epic, spike, and ADR-0022 — this ticket is customer/support-facing docs, not engineering design docs.
• Any documentation for self-hosted/non-Cloud deployments (out of scope for the whole epic).

Dependencies

The dashboard-docs and configuration-reference pieces need the dotCMS-core and Dashboard sub-tasks' final behavior to be accurate — draft against their specs once available, don't block entirely on implementation completing. The data-reset notice is not blocked on the other sub-tasks and should be drafted and reviewed early, since it's a hard release gate per the epic's acceptance criteria.

Acceptance Criteria

• Dashboard docs describe the environment selector, its default, and how to change it
• Configuration reference documents both env vars and the curation/self-healing behavior for Platform/support
• Data-reset notice published and reviewed before the release ships (epic acceptance criterion — not after)
• Docs reviewed against the actual shipped behavior of the core/dashboard sub-tasks before publishing (not just the design intent)

Next step

Run /speckit-specify against this issue to produce the formal spec (doc structure, publishing location, review/sign-off process) before drafting.