Overhaul code org, and improve image uploading

This commit introduces breaking changes. It overhauls how and where
services are configured and placed in the codebase, as well as moving
the entire source into src/ It also changes how these integrations
are configured via environment variables. Old configs will still work
for now, but it is strongly suggested that you migrate your config.

go.mod

@@ -5,6 +5,7 @@ go 1.25.0
 require (
 	github.com/HugoSmits86/nativewebp v1.2.0
 	github.com/caarlos0/env/v11 v11.3.1
+	golang.org/x/image v0.24.0
 	modernc.org/sqlite v1.39.0
 )
 
@@ -19,7 +20,6 @@ require (
 	github.com/tinylib/msgp v1.4.0 // indirect
 	golang.org/x/crypto v0.42.0 // indirect
 	golang.org/x/exp v0.0.0-20250620022241-b7579e27df2b // indirect
-	golang.org/x/image v0.24.0 // indirect
 	golang.org/x/net v0.44.0 // indirect
 	golang.org/x/text v0.29.0 // indirect
 	modernc.org/libc v1.66.3 // indirect
@@ -41,7 +41,6 @@ require (
 	github.com/mattn/go-colorable v0.1.14 // indirect
 	github.com/mattn/go-isatty v0.0.20 // indirect
 	github.com/mattn/go-runewidth v0.0.15 // indirect
-	github.com/nfnt/resize v0.0.0-20180221191011-83c6a9932646
 	github.com/rivo/uniseg v0.2.0 // indirect
 	github.com/valyala/bytebufferpool v1.0.0 // indirect
 	github.com/valyala/fasthttp v1.66.0 // indirect