fix: parse numeric environment variables to correct types

[LautaroPetaccio]

Summary

Several numeric environment variables were stored as strings when set via process.env, but as numbers when using the default value. Consumers read them with getConfig<number>(...), which silently receives a string. JavaScript coercion often makes this work, but it causes incorrect behavior in strict comparisons and library APIs that expect numbers.

Changes in Environment.ts:

Config	Fix
FOLDER_MIGRATION_MAX_CONCURRENCY	Number(...) with fallback
HTTP_SERVER_PORT	Number(...) with fallback
UPDATE_FROM_DAO_INTERVAL	ms(... ?? '30m') to parse duration strings
DEPLOYMENTS_DEFAULT_RATE_LIMIT_MAX	Number(...) with fallback
PSQL_PORT	Number(...) with fallback
ENTITIES_CACHE_SIZE	Number(...) with fallback
DEPLOYMENT_RATE_LIMIT_MAX per-entity	parseInt(value!, 10) replacing value as any as number
RETRY_FAILED_DEPLOYMENTS_DELAY_TIME	ms(... ?? '15m') to parse duration strings

Also fixes the requireNumber error message which incorrectly said "string" instead of "number".

Test plan

• Set env vars like HTTP_SERVER_PORT=7070 and verify they're stored as numbers
• Verify default values still work when env vars are unset
• Run unit tests: cd content && npx jest test/unit/ --no-coverage