2c: Add release_health DB table + queries

[ajianaz]

Parent: #232 · Blocked by: #240

Scope

Database schema and queries for storing session/release health data.

New Table: release_health

Column	Type	Notes
id	TEXT PK	uuid
project_id	TEXT FK→projects
release	TEXT NOT NULL	"rungu@0.2.0"
environment	TEXT	"production", "development"
started_at	TEXT NOT NULL	window start (from aggregate)
distinct_id	TEXT	null = aggregated across all users
exited	INTEGER DEFAULT 0
errored	INTEGER DEFAULT 0
abnormal	INTEGER DEFAULT 0
crashed	INTEGER DEFAULT 0
received_at	TEXT NOT NULL

Indexes: (project_id), (project_id, release, environment)

Optional: session_updates (raw individual sessions)

Column	Type	Notes
id	TEXT PK
project_id	TEXT FK
session_id	TEXT
distinct_id	TEXT
init	BOOLEAN
started	TEXT
duration	REAL
status	TEXT
errors	INTEGER
release	TEXT
environment	TEXT
received_at	TEXT

Queries to Add

• insert_release_health(project_id, aggregates) — bulk insert from SessionAggregates
• get_crash_rate(project_id, release, env, window_hours) → crash rate percentage
• list_release_health(project_id, release?, env?, page, per_page)
• get_release_summary(project_id) → per-release crash rate summary

Tasks

• SQLite migration: 004_release_health.sql
• Postgres migration: same
• Add insert + query functions
• Add tests: insert aggregated session → retrieve crash rate
• Add test: crash rate = crashed / total × 100

Effort: ~2 hours