Supervision tree

Defined in lib/speechwave/application.ex. Children start in order, top to bottom. Strategy: :one_for_one (restart only the crashed child).

Children (boot order)

Child	What it does	Why this position
`SpeechwaveWeb.Telemetry`	Collects metrics (request times, VM stats). Powers the `/dev/dashboard` LiveDashboard graphs.	First: so it can observe everything that follows.
`Speechwave.Repo`	Database connection pool (SQLite via Ecto).	Must start before anything that queries the DB.
`{DNSCluster, ...}`	Discovers other nodes via DNS for clustering.	Disabled in dev (`:ignore`). Used in production for multi-node discovery.
`{Phoenix.PubSub, ...}`	Publish/subscribe system. `TalkLive` subscribes to this for real-time emoji broadcasts.	Must start before the Endpoint (which depends on it).
`Speechwave.RateLimiter`	GenServer owning the ETS table for emoji tap rate limiting (a short cooldown).	Before Endpoint: must be ready when LiveViews start handling taps.
`Speechwave.AuthThrottle`	GenServer owning ETS tables for magic-link email and IP-based login throttling (escalating on repeated attempts).	Before Endpoint: must be ready when login requests arrive.
`SpeechwaveWeb.Endpoint`	The HTTP server (Bandit). Listens for connections, handles WebSocket upgrades for LiveView.	Near the end: only accepts traffic when everything above is ready.
`SpeechwaveWeb.Presence`	Tracks connected users per topic (built on PubSub). Used for audience counts.	After Endpoint and PubSub are running.
`Speechwave.DbBackup`	Periodic SQLite backup to S3 (5 min initial delay, then hourly).	Conditional: only added once storage is configured (production only).

Supervision strategies

Strategy	On child crash
`:one_for_one`	Restart only the crashed child (Speechwave uses this)
`:one_for_all`	Restart all children
`:rest_for_one`	Restart the crashed child and all children started after it

Child spec formats

# Module name: calls Module.start_link([])
Speechwave.RateLimiter

# Tuple: passes options to Module.start_link(opts)
{Phoenix.PubSub, name: Speechwave.PubSub}

# Conditional children
if condition, do: [Speechwave.DbBackup], else: []