Sadaliak

Sadaliak is a star on the very edge of human-inhabited space. First scouted by a UNM ranger in 2236, the official report described eleven major planets, including six gas giants, two ice planets and three standard terrestrial planets. One of those, Sadaliak b, was rated "probably habitable" although ongoing resource constraints limited further investigation. The report was filed away and ignored.
In 2248, the IP3 Starblade Long March of Progress placed a new wormhole gate in the Sadaliak system against the orders of the local parliament. Unofficially, the commander in charge of the station had received a copy of the UNM scouting report and decided to claim the system for the IP3 without first asking anyone for permission. Officially, it was a matter of miscommunication and a lucky coincidence the wormhole ended up in a star system with a habitable planet and not deep space. Wormholes are expensive, and so the IP3 wasted no time in sending a research and exploration team to investigate Sadliak b.
They found a planet on the edge of human habitability. Its local fauna were, strictly speaking, poisonous to humans. The ozone layer was dangerously thin, requiring potential colonists to cover up or risk significant burns anywhere within 20 degrees of the equator. However the planet had large areas suitable for industrial farming, plenty of easily accessible mineral and metal deposits in near-planetary objects, and with a surface gravity of 0.7G it would be trivial to produce an orbital elevator to allow for cheap access to orbit.
In 2249, the first colony drop ship arrived bringing 60,000 people and enough prefab housing to keep them warm and dry. They landed on a peninsula in the northern tropics and established Baxter City. Colony drop ships were single use starships, bolted together from prefab houses, schools, offices, workshops and everything else a new colony might need. The reactor became a power plant. The engines became foundries. The superstructure of the ship was designed to be re-purposed into roads and bridges.
The initial colonists would suffer somewhat from a lack of direction. Most new colonies were planned years in advance, but Sadaliak was rushed. Over the following eight years, another 190,000 colonists would arrive. There was an early push to kickstart an agricultural industry, the orbital elevator made it easy to export stuff from the planet's surface and the low gravity allowed human plants to grow to absurd sizes. By 2253, a mere five years after founding, the planet was exporting food to nearby systems and nearly self sustaining (or at least making enough through trade to buy in what they needed without relying on subsidies).
Other industry continues to lag behind however. An early start producing high value electronics faltered when nearby Menkalhault unveiled a new unified orbital shipyard complex which could produce anything they could on Sadaliak faster and cheaper. Continuing issues with the local fauna limit other heavy industry, although the production of adapted ground vehicles for farming was growing year on year. Other agricultural planets were starting to take stock, and whilst exports were slow, they were also growing.
Despite the relative prosperity, a shadow loomed over the colony. In 2252, a UNM delegation arrived in the system with a cadre of lawyers. They, they stated, had scouted the system first. The fact they'd sat on the records for nearly twenty years didn't matter, as per interstellar law the system belonged to the UNM until they said otherwise. The IP3 protested but they didn't have a legal leg to stand on, and to make matters worse prospectors had uncovered significant deposits of rare and valuable minerals in the system's asteroid belt. Materials that were of great use for constructing fusion reactors. The UNM offered a deal, consent to the UNM establishing a military garrison in the asteroid belt and sign over rights to any deposits found there, and the IP3 could keep the planet, and anything they found elsewhere in the system.
Whilst all this was happening, the UNM moved in both the engineers and the garrison and for four long years the system was plagued by routine skirmishes as IP3 warships pushed the boundaries of the UNM garrison, flying as close as they dared and dared the UNM ships to respond to their obvious provocation. The UNM were no better, regularly stationing over a hundred ships in the system for no real reason. There was never outright war, but shots were fired and lives were lost. There were two major incidents. One IP3 Union class frigate was destroyed after a "freedom of navigation" exercise resulted in a firefight, with the loss of all hands and the death of 72 voidsailors. Two UNM Planetary class Corvettes were destroyed playing cat and mouse with an IP3 patrol in a dense asteroid cluster, resulting in 34 deaths and a further 28 injuries.
In early 2257, the two powers signed the Sadiliak Deep Space Treaty, limiting the UNM garrison and forbidding IP3 provocation, and whilst it's still early days the treaty seems to be holding.