refactor(db): port operations, settings, audit, and misc metadata to sqlc (#84)

* refactor(db): port operations, settings, audit, activity, and misc service metadata to sqlc

Covers the cross-cutting surface: operations board reads, app settings,
notification producers, activity/audit inserts, builds upsert/cancel,
git clone credential resolution, invites, environments, registry auth,
project/service variables, HA resolver, boot sweeps, and admin user ops.
Dynamic filtered lists and Better Auth table probes stay raw by design.

Authored By: TDvorak <[email protected]>

* refactor(db): port apwhy gateway handlers and proxy data plane to sqlc

Final tranche — every static call site now uses generated queries. Raw SQL
remains only where the statement is assembled at runtime (filtered lists,
sparse updates, admin count closure) or probes Better Auth's auth_users
table, which lives outside the local schema.

Authored By: TDvorak <[email protected]>

app/backend/internal/api/invites.go

@@ -193,8 +193,8 @@ func handleAcceptInvite(c *gin.Context) {
 		return
 	}
 
-	var existing int
-	if err := db.QueryRow(`SELECT COUNT(*) FROM users WHERE email = $1`, req.Email).Scan(&existing); err != nil {
+	existing, err := q.CountUsersByEmail(c.Request.Context(), req.Email)
+	if err != nil {
 		respondError(c, http.StatusInternalServerError, "INTERNAL", "database error")
 		return
 	}
@@ -214,17 +214,23 @@ func handleAcceptInvite(c *gin.Context) {
 		return
 	}
 
-	var user User
-	err = db.QueryRow(`
-		INSERT INTO users (email, password_hash, name)
-		VALUES ($1, $2, $3)
-		RETURNING id, email, name, COALESCE(avatar_url, ''), is_admin, created_at
-	`, req.Email, string(hashedPassword), strings.TrimSpace(req.Name)).
-		Scan(&user.ID, &user.Email, &user.Name, &user.AvatarURL, &user.IsAdmin, &user.CreatedAt)
+	row, err := q.InsertUser(c.Request.Context(), sqlcdb.InsertUserParams{
+		Email:        req.Email,
+		PasswordHash: string(hashedPassword),
+		Name:         strings.TrimSpace(req.Name),
+	})
 	if err != nil {
 		respondError(c, http.StatusConflict, "CONFLICT", "user already exists")
 		return
 	}
+	user := User{
+		ID:        row.ID.String(),
+		Email:     row.Email,
+		Name:      row.Name,
+		AvatarURL: row.AvatarUrl,
+		IsAdmin:   row.IsAdmin,
+		CreatedAt: row.CreatedAt.Time.String(),
+	}
 
 	userUUID, _ := uuid.Parse(user.ID)
 	if err := q.MarkUserInviteUsed(c.Request.Context(), sqlcdb.MarkUserInviteUsedParams{