v3.25.2
Redeemable Convertible Preferred Stock and Stockholders' Deficit - Stock Option Plan Activity (FY) (Details) - USD ($)
$ / shares in Units, $ in Thousands
 6 Months Ended 12 Months Ended
Jun. 30, 2025
Jun. 30, 2024
Dec. 31, 2024
Dec. 31, 2023
Dec. 31, 2022
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding [Roll Forward]          
Beginning balance (in shares) 47,219,000 51,239,000 51,239,000 32,655,000  
Granted (in shares) 0 0 0 23,300,000  
Exercised (in shares) (2,950,000)   (2,872,000) (4,337,000)  
Forfeited, expired, or canceled (in shares) (164,000)   (1,148,000) (379,000)  
Ending balance (in shares) 44,105,000   47,219,000 51,239,000 32,655,000
Vested and expected to vest (in shares) 44,105,000   47,219,000 51,239,000  
Exercisable (in shares) 31,596,000   31,019,000 24,356,000  
Weighted-Average Exercise Price          
Options outstanding, Weighted average exercise price per share - beginning balance (in usd per share) $ 1.74 $ 1.75 $ 1.75 $ 0.33  
Granted (in dollars per share) 0   0 3.48  
Exercised (in dollars per share) 1.53   1.01 0.38  
Forfeited, expired, or canceled (in dollars per share) 6.62   4.05 1.7  
Options outstanding, Weighted average exercise price per share - ending balance (in usd per share) 1.74   1.74 1.75 $ 0.33
Vested and expecting to vest (in dollars per share) 1.74   1.74 1.75  
Exercisable (in dollars per share) $ 1.14   $ 0.98 $ 0.37  
Stock Options Additional Disclosures          
Outstanding, Weighted average remaining contractual term 7 years   7 years 8 years 8 years
Vested and expected to vest, Weighted average remaining contractual term 7 years   7 years 8 years  
Exercisable, Weighted average remaining contractual term 6 years   6 years 6 years  
Outstanding, Aggregate intrinsic value $ 7,114,827   $ 2,163,455 $ 795,013 $ 20,770
Vested and expecting to vest, Aggregate intrinsic value 7,114,827   2,163,455 795,013  
Exercisable, Aggregate intrinsic value $ 5,116,131   $ 1,444,794 $ 411,567