[Feat] Track setup funnel progress

[roomote-roomote]

Created by Roomote. Follow up by mentioning @roomote-roomote, in the web UI, or in Slack.

What changed

• Adds instance-level activation milestones for welcome, authenticated setup, communications configuration and connection, source-control configuration and connection, inference configuration, and sandbox configuration.
• Derives achieved milestones from the setup wizard's authoritative provider status, including saved-only provider fallbacks and cache-fresh server verification for Teams, Telegram, and Discord.
• Persists milestone timestamps in deployment metadata under an advisory lock so each deployment emits each milestone once, while retaining the existing setup-completed and activation events.
• Documents the additional anonymous setup telemetry and adds focused coverage for deduplication, preconfigured providers, bootstrap gating, and provider-specific setup paths.

Why this change was made

The existing activation events only showed setup completion and later outcomes. These milestones reveal where deployments stop during setup, including optional provider steps, without collecting identifying configuration data.

Impact

Roomote can build a deployment-level setup funnel using non-identifying provider classifications. Existing analytics opt-out and environment gates still apply, preconfigured provider state is tagged where it can be determined authoritatively, and the setup UI behavior is unchanged.

[roomote-community]

No new code issues found. See task

• apps/web/src/lib/server/setup-funnel-telemetry.ts:84-125 Saved-only auth and source-control providers now fall back to the authoritative preselectedProvider.
• apps/web/src/app/(onboarding)/setup/StepTelegramSetup.tsx:53-57 Telegram milestone verification now clears the runtime-credential cache before reading the saved credentials.

_{Reviewed b6727e1}

[roomote-roomote]

Fixed both outstanding review findings:

• saved-only communications and source-control setup now fall back to the authoritative preselectedProvider
• Telegram milestone verification invalidates the runtime credential cache in the verifying server request before reading the saved token

Focused tests, type checks, lint, and the pre-push suite pass. Pushed in b6727e1.