[feature] update proof-of-work to allow setting required rounds (#4186)

# Description

This updates our proof-of-work middleware, NoLLaMas, to work on a more easily configurable algorithm (thank you f0x for bringing this to my attention!). Instead of requiring that a solution with pre-determined number of '0' chars be found, it now pre-computes a result with a pre-determined nonce value that it expects the client to iterate up-to. (though with some level of jitter applied, to prevent it being too-easily gamed). This allows the user to configure roughly how many hash-encode rounds they want their clients to have to complete.

## Checklist

- [x] I/we have read the [GoToSocial contribution guidelines](https://codeberg.org/superseriousbusiness/gotosocial/src/branch/main/CONTRIBUTING.md).
- [x] I/we have discussed the proposed changes already, either in an issue on the repository, or in the Matrix chat.
- [x] I/we have not leveraged AI to create the proposed changes.
- [x] I/we have performed a self-review of added code.
- [x] I/we have written code that is legible and maintainable by others.
- [x] I/we have commented the added code, particularly in hard-to-understand areas.
- [x] I/we have made any necessary changes to documentation.
- [ ] I/we have added tests that cover new code.
- [x] I/we have run tests and they pass locally with the changes.
- [x] I/we have run `go fmt ./...` and `golangci-lint run`.

Reviewed-on: https://codeberg.org/superseriousbusiness/gotosocial/pulls/4186
Co-authored-by: kim <grufwub@gmail.com>
Co-committed-by: kim <grufwub@gmail.com>

vendor/codeberg.org/gruf/go-bitutil/test.tpl

@@ -0,0 +1,60 @@
+package atomics_test
+
+import (
+    "atomic"
+    "unsafe"
+    "testing"
+
+    "codeberg.org/gruf/go-atomics"
+)
+
+func Test{{ .Name }}StoreLoad(t *testing.T) {
+    for _, test := range {{ .Name }}Tests {
+        val := atomics.New{{ .Name }}()
+
+        val.Store(test.V1)
+
+        if !({{ call .Compare "val.Load()" "test.V1" }}) {
+            t.Fatalf("failed testing .Store and .Load: expect=%v actual=%v", val.Load(), test.V1)
+        }
+
+        val.Store(test.V2)
+
+        if !({{ call .Compare "val.Load()" "test.V2" }}) {
+            t.Fatalf("failed testing .Store and .Load: expect=%v actual=%v", val.Load(), test.V2)
+        }
+    }
+}
+
+func Test{{ .Name }}CAS(t *testing.T) {
+    for _, test := range {{ .Name }}Tests {
+        val := atomics.New{{ .Name }}()
+
+        val.Store(test.V1)
+
+        if val.CAS(test.V2, test.V1) {
+            t.Fatalf("failed testing negative .CAS: test=%+v state=%v", test, val.Load())
+        }
+
+        if !val.CAS(test.V1, test.V2) {
+            t.Fatalf("failed testing positive .CAS: test=%+v state=%v", test, val.Load())
+        }
+    }
+}
+
+func Test{{ .Name }}Swap(t *testing.T) {
+    for _, test := range {{ .Name }}Tests {
+        val := atomics.New{{ .Name }}()
+
+        val.Store(test.V1)
+
+        if !({{ call .Compare "val.Swap(test.V2)" "test.V1" }}) {
+            t.Fatal("failed testing .Swap")
+        }
+
+        if !({{ call .Compare "val.Swap(test.V1)" "test.V2" }}) {
+            t.Fatal("failed testing .Swap")
+        }
+    }
+}
+