Refine connector provider registry per review

Three follow-ups from review of the registry consolidation:

- Build Vercel's authorization URL with net/url instead of a
  hand-rolled "{integration_slug}" placeholder resolved by
  strings.ReplaceAll. The slug is escaped via url.PathEscape in a
  per-provider Registration.BuildAuthURL closure, and the unused
  AuthURLParams plumbing on Registration and OAuth2Connector is
  removed (OAuth2Connector now carries a typed IntegrationSlug).

- Drop the SettingsInput union type and the per-provider
  MarshalSettings closures. The create resolvers now build the typed
  coredata.*ConnectorSettings directly from the gqlgen input, the
  same way the OAuth callback path already does, so there is no
  shared catch-all DTO and no stringly-typed boundary.

- Restore ConnectorProviders() to a plain ordered slice literal; the
  intermediate map + slices.Sort added nondeterminism and a sort for
  no benefit.

Signed-off-by: Aurélien Sibiril <81782+aureliensibiril@users.noreply.github.com>

pkg/coredata/connector_provider.go

@@ -17,7 +17,6 @@ package coredata
 import (
 	"encoding"
 	"fmt"
-	"slices"
 )
 
 type ConnectorProvider string
@@ -58,50 +57,35 @@ var (
 	_ encoding.TextUnmarshaler = (*ConnectorProvider)(nil)
 )
 
-// providerStringMap is the single source of truth that connects the
-// wire/string form of a ConnectorProvider to its typed constant. Both
-// ConnectorProviders() and Scan() read from it; adding a new provider
-// is one constant + one map entry.
-var providerStringMap = map[string]ConnectorProvider{
-	"SLACK":            ConnectorProviderSlack,
-	"GOOGLE_WORKSPACE": ConnectorProviderGoogleWorkspace,
-	"LINEAR":           ConnectorProviderLinear,
-	"ONE_PASSWORD":     ConnectorProviderOnePassword,
-	"HUBSPOT":          ConnectorProviderHubSpot,
-	"DOCUSIGN":         ConnectorProviderDocuSign,
-	"NOTION":           ConnectorProviderNotion,
-	"BREX":             ConnectorProviderBrex,
-	"TALLY":            ConnectorProviderTally,
-	"CLOUDFLARE":       ConnectorProviderCloudflare,
-	"OPENAI":           ConnectorProviderOpenAI,
-	"SENTRY":           ConnectorProviderSentry,
-	"SUPABASE":         ConnectorProviderSupabase,
-	"GITHUB":           ConnectorProviderGitHub,
-	"INTERCOM":         ConnectorProviderIntercom,
-	"RESEND":           ConnectorProviderResend,
-	"MICROSOFT_365":    ConnectorProviderMicrosoft365,
-	"GITLAB":           ConnectorProviderGitLab,
-	"BITBUCKET":        ConnectorProviderBitbucket,
-	"HEROKU":           ConnectorProviderHeroku,
-	"PAGERDUTY":        ConnectorProviderPagerDuty,
-	"ASANA":            ConnectorProviderAsana,
-	"NETLIFY":          ConnectorProviderNetlify,
-	"CLICKUP":          ConnectorProviderClickUp,
-	"VERCEL":           ConnectorProviderVercel,
-	"MONDAY":           ConnectorProviderMonday,
-}
-
 func ConnectorProviders() []ConnectorProvider {
-	out := make([]ConnectorProvider, 0, len(providerStringMap))
-	for _, v := range providerStringMap {
-		out = append(out, v)
+	return []ConnectorProvider{
+		ConnectorProviderSlack,
+		ConnectorProviderGoogleWorkspace,
+		ConnectorProviderLinear,
+		ConnectorProviderOnePassword,
+		ConnectorProviderHubSpot,
+		ConnectorProviderDocuSign,
+		ConnectorProviderNotion,
+		ConnectorProviderBrex,
+		ConnectorProviderTally,
+		ConnectorProviderCloudflare,
+		ConnectorProviderOpenAI,
+		ConnectorProviderSentry,
+		ConnectorProviderSupabase,
+		ConnectorProviderGitHub,
+		ConnectorProviderIntercom,
+		ConnectorProviderResend,
+		ConnectorProviderMicrosoft365,
+		ConnectorProviderGitLab,
+		ConnectorProviderBitbucket,
+		ConnectorProviderHeroku,
+		ConnectorProviderPagerDuty,
+		ConnectorProviderAsana,
+		ConnectorProviderNetlify,
+		ConnectorProviderClickUp,
+		ConnectorProviderVercel,
+		ConnectorProviderMonday,
 	}
-
-	// Map iteration order is nondeterministic; sort so callers (e.g. the
-	// connectorProviderInfos API/UI listing) get a stable order.
-	slices.Sort(out)
-
-	return out
 }
 
 func (v ConnectorProvider) IsValid() bool {