Update tool dependencies and fix new lint issues (#36702)

## Summary
- Update golangci-lint v2.9.0 → v2.10.1, misspell v0.7.0 → v0.8.0,
actionlint v1.7.10 → v1.7.11
- Fix 20 new QF1012 staticcheck findings by using `fmt.Fprintf` instead
of `WriteString(fmt.Sprintf(...))`
- Fix SA1019: replace deprecated `ecdsa.PublicKey` field access with
`PublicKey.Bytes()` for JWK encoding, with SEC 1 validation and curve
derived from signing algorithm
- Add unit test for `ToJWK()` covering P-256, P-384, and P-521 curves,
also verifying correct coordinate padding per RFC 7518
- Remove dead staticcheck linter exclusion for "argument x is
overwritten before first use"

## Test plan
- [x] `make lint-go` passes with 0 issues
- [x] `go test ./services/oauth2_provider/ -run
TestECDSASigningKeyToJWK` passes for all curves

🤖 Generated with [Claude Code](https://claude.com/claude-code)

---------

Co-authored-by: Claude Opus 4.6 <noreply@anthropic.com>

services/gitdiff/gitdiff.go

@@ -1594,10 +1594,10 @@ func generatePatchForUnchangedLineFromReader(reader io.Reader, treePath string,
 
 	// Generate synthetic patch
 	var patchBuilder strings.Builder
-	patchBuilder.WriteString(fmt.Sprintf("diff --git a/%s b/%s\n", treePath, treePath))
-	patchBuilder.WriteString(fmt.Sprintf("--- a/%s\n", treePath))
-	patchBuilder.WriteString(fmt.Sprintf("+++ b/%s\n", treePath))
-	patchBuilder.WriteString(fmt.Sprintf("@@ -%d,%d +%d,%d @@\n", startLine, len(lines), startLine, len(lines)))
+	fmt.Fprintf(&patchBuilder, "diff --git a/%s b/%s\n", treePath, treePath)
+	fmt.Fprintf(&patchBuilder, "--- a/%s\n", treePath)
+	fmt.Fprintf(&patchBuilder, "+++ b/%s\n", treePath)
+	fmt.Fprintf(&patchBuilder, "@@ -%d,%d +%d,%d @@\n", startLine, len(lines), startLine, len(lines))
 
 	for _, lineContent := range lines {
 		patchBuilder.WriteString(" ")