[Bug Report] panic during error handling on second startup

[Dobatymo]

Describe the bug

Calling stash-box on second start-up with wrong password or non existent database results in panic.

>stash-box-windows.exe
panic: failed to open database, "postgres://postgres@localhost/stash-box?sslmode=disable": pq: Passwort-Authentifizierung f�r Benutzer �postgres� fehlgeschlagen [password authentication for user failed]
        panic: runtime error: invalid memory address or nil pointer dereference
[signal 0xc0000005 code=0x0 addr=0x0 pc=0xd90083]

goroutine 1 [running]:
main.main.deferwrap1()
        /home/runner/work/stash-box/stash-box/main.go:28 +0x23
panic({0xe2c500?, 0xc0005a2090?})
        /opt/hostedtoolcache/go/1.23.11/x64/src/runtime/panic.go:791 +0x132
github.com/stashapp/stash-box/pkg/database.(*PostgresProvider).runMigrations(0x18?, {0xc00002ea20, 0x2c})
        /home/runner/work/stash-box/stash-box/pkg/database/postgres.go:77 +0x1a6
github.com/stashapp/stash-box/pkg/database.(*PostgresProvider).Open(0xe91f40?, {0xc00002ea20, 0x2c})
        /home/runner/work/stash-box/stash-box/pkg/database/postgres.go:34 +0x32
github.com/stashapp/stash-box/pkg/database.Initialize({0x101be4c, 0x8}, {0xc00002ea20, 0x2c})
        /home/runner/work/stash-box/stash-box/pkg/database/database.go:22 +0x64
main.main()
        /home/runner/work/stash-box/stash-box/main.go:33 +0xec

>stash-box-windows.exe
panic: failed to open database, "postgres://postgres:xxx@localhost/stash-box?sslmode=disable": pq: Datenbank �stash-box� existiert nicht [database does not exist]
        panic: runtime error: invalid memory address or nil pointer dereference
[signal 0xc0000005 code=0x0 addr=0x0 pc=0xd90083]

goroutine 1 [running]:
main.main.deferwrap1()
        /home/runner/work/stash-box/stash-box/main.go:28 +0x23
panic({0xe2c500?, 0xc0004ea010?})
        /opt/hostedtoolcache/go/1.23.11/x64/src/runtime/panic.go:791 +0x132
github.com/stashapp/stash-box/pkg/database.(*PostgresProvider).runMigrations(0x18?, {0xc000120100, 0x33})
        /home/runner/work/stash-box/stash-box/pkg/database/postgres.go:77 +0x1a6
github.com/stashapp/stash-box/pkg/database.(*PostgresProvider).Open(0xe91f40?, {0xc000120100, 0x33})
        /home/runner/work/stash-box/stash-box/pkg/database/postgres.go:34 +0x32
github.com/stashapp/stash-box/pkg/database.Initialize({0x101be4c, 0x8}, {0xc000120100, 0x33})
        /home/runner/work/stash-box/stash-box/pkg/database/database.go:22 +0x64
main.main()
        /home/runner/work/stash-box/stash-box/main.go:33 +0xec

To Reproduce

1. start stash-box first time to create default config
2. have password on postgres user on postgres db
3. start stash-box second time (first error)
4. add password to connection string
5. start stash-box again (second error)

Expected behavior
just show the normal error message and don't panic

Screenshots

Desktop (please complete the following information):

• OS: Windows 11 x64
• Browser: not used
• Version v0.6.17 - 2025-08-10 09:22:42

Additional context